After 5 years of use:

Negatives
1. The bag can only be worn with sweatshirts, jackets, or anything with a collar because its strap does not stay in place at all on t-shirts.
2. It has an open-type hook for detaching the strap, so with intense movements it comes off.
3. When fully loaded, it has a poor center of gravity and sticks out quite a bit.

Positives
1. Honestly waterproof
2. Good as a second bag

I use the miltec which, although it has more liters, fits and holds better, and also has an excellent strap that does not cut into you.

Quality and very practical!

The bag, for its size, fits a lot of things—I have even managed to fit a windbreaker and a thin cardigan along with the many other things I put inside. The quality is excellent and it is very convenient. As for the hook, I didn't have any issues, but just to be completely sure, I simply sewed the fabric a bit at the spot where you take it out so it would be tighter, even though, as I said, it never came out of place.

The best thing I have bought in a chest bag.

Very user-friendly and with plenty of space for various items (agenda, mobile phone, wallet, keys, documents, baby wipes, etc.)

Very convenient bag, you can easily convert it to a backpack or shoulder bag due to the many loops it has on the sides for the strap. The compartments have sufficient dividers so you don't constantly search for where each item is, and the space is very satisfactory. The price-quality ratio is good, and I believe that for its category, it is worth the money you will spend for the use of the bag.

Very good quality and with enough space for its size, the only downside is its hook that comes off relatively easily

I can't understand some schools. I have had the bag for 3 years. I have no absolute problem. I have run with the engine fearlessly for 220 km!!!!. Now regarding the hook. Probably some people don't know how to pass it correctly as they should. Personally, it has served me and will continue to do its job, like a big, spacious bag. It was worth every CENT I gave..

Pentagon, what can we say...
Quality!!!
Very nice little bag with large spaces and compartments for various things.

Good, you don't want anything more, it covers you perfectly. The only problem, which is also very serious, is the clasp. It simply falls off while walking. If you have it on the bike and it comes off, goodnight. Whoever came up with the idea... unemployment line yesterday

Spacious bag and quite good quality.
It is definitely better than other brand bags that cost around 20 euros on the market... without meaning that the 40 euros it asks for is too little.
I didn't have any problem with the handle coming off while I'm on the bike or during use.
What I did was sew the bottom part of the handle slot to make it a bit tighter but at the same time still removable when I want it, and that was it.... 5 minutes of work for anyone who is unsure.
Recommended.

Good in quality, space, and durable zippers, but somewhere the issue becomes excessive. To have purchased a 7-liter bag two years ago for 25 euros - which objectively is its value - and today it costs 42 euros. It is very expensive.

The old model was excellent, but this UCB 2.0 is not, and I will explain why immediately. Firstly and most importantly, the previous model had a very sturdy and secure attachment system that safely held the bag in place in any condition. However, this particular model has a terrible flaw, a loose flat S-shaped hook that comes off with the slightest movement or pull, which is very dangerous as it could cause the bag to fall off while on the road, especially if you are riding a motorcycle with all that entails. This alone is enough reason for someone not to prefer it. Additionally, the gray lining inside, apart from being tasteless, looks (and is) fake compared to the previous model. Furthermore, the previous model's Velcro inner pocket, which was very convenient for securing small items, is also missing. The quality has also been downgraded. It's a shame that Pentagon ruined such a successful bag by raising the price and lowering the quality

After 3.5 years of hard daily use in mountains, seas, rain, and deliveries, only one zipper broke because I opened and closed it at least 50 times during my shift. I decided to replace it after all these years. Incredible functionality and capacity, the best little bag I have ever tried.

Excellent durability and quality bag, with plenty of compartments for small items, can also fit a pocket notebook.

For its price, it does not offer much capacity. I suppose the essence lies in the materials and its durability, which I will judge over time.
What doesn't sit well with me is the choice of colors for the Pentagon. The Coyote and Khaki don't know if they want to be brown or khaki. Both are something in between but not exactly what I want. As shown in the photos I provided, only the Kyvos is khaki and it still doesn't match well with the UCB 2.0.
Furthermore, the side molle straps are neither the same width nor user-friendly; they seem more decorative. There is a lack of space where I placed the Kyvos, and there is actually more space in other larger and cheaper chest bags.
There should be a strap with a clip that holds the central belt/strap in place so that it doesn't slip. Something that another cheaper backpack has. Maybe I can fix it with 2-3 meters of paracord and, for example, a Cobra weave to make it more sturdy.
It's not bad, but it's more overhyped due to its name.

The bag is top-notch.. my friend saw it and wanted me to order him the same color..
And now we're walking around the village matching xxxxx.... you should get it with your eyes closed...!!!!!

A little bulky, but quite convenient since it can fit a lot of things (book, notebook, water bottle, glasses, etc). Its durability will be evident over time, for now, it holds up well.

Very good bag, durable and very convenient, I have it in front but it also helps me on my back, practical pockets and strong seams. I had ordered it with a hook but it came with a clip, in the end I have no problem, the hook may not have been so secure. I carry my daily things and there is also space for other various items. Bravo to the company

Very spacious with many compartments to distribute your personal items and not have them all loose. It fits all the essentials like phone, keys, wallet, pen, and many more. The quality of construction is quite good and personally, I like its discreet appearance.

For the money I got it, around 30 with a difference, the best little bag! Top in durability.. I also have Maxpedition bags, this one has nothing to envy.. I would prefer it a little bigger but that's my own obsession!!

Very comfortable, lots of pockets and small compartments to put everything. It can withstand a lot of weight. The main strap bothers me a little, as it hooks onto the bag, so if you make a sudden movement or anything, the bag can come off

Very convenient and beautiful in appearance, a wallet for papers/documents, keys, and water all together. Very satisfied

Incredibly convenient, very stylish, comfortable, with many useful pockets. Overall, there is nothing negative, only positives!

I have had it since 2017 and I can confidently say that it is the best in terms of quality and durability that I have ever had. It is extremely well-designed with two compartments, a large one with 2 partitions inside and a small one (in the front) that also has partitions and seams for placing keys, pens, knives, and many other things. It also has one on the back. It is a chest bag, but when you remove the adjustable strap, it becomes a handbag. It is not particularly small, but it is not very big either, depending on what each person is accustomed to. It is tactical, which makes it look somewhat rugged, but personally, I use it everywhere and always without any issues. It is so durable that you trust it and it gives you the feeling that it will accompany you for years. Overall, I have not found any negatives so far, except perhaps for its weight, depending on how much and what you load it with. Here is the detailed presentation I have made: https://youtu.be/4uTmmusezLY

Excellent quality! Only two things I would like to note. 1) I would prefer it to be slightly larger in terms of capacity and 2) it doesn't sit high enough on the chest or back. It falls too low. Unless I am doing something wrong.