This is my 4th switch of this kind. I already had three of them for a while and I decided to get another one.
As for the construction, it's great! It works perfectly fine and the price is also great! I highly recommend it!

Personally, I would like it to have more features, such as:

It only has 3 types of control: single press, double press (in a row), and long press. I mean, usually these 3 types of control are enough for a switch. However, I don't see the reason why one should be limited to only these three types of control when it could easily have more, for example, more than 2 consecutive presses.

The design is nice and minimal! However, I would like to be able to find it in smaller and larger sizes, as well as in different colors or with different designs. I don't think it would be so "strange" for them to offer these options.

Its communication is only wireless and only through a Xiaomi Control hub, using Zigbee technology. On one hand, this makes it very lightweight and compact, but on the other hand, it makes it exclusively for use with the Xiaomi Home app. It is not "visible" (as a home smart device) in the broader smart home ecosystem (Google Home, Alexa, etc.). I should mention that this "communication approach" is the same for other Xiaomi devices, such as motion sensors, etc.

The way it opens to change its battery (which fortunately doesn't need to be done frequently for each switch) is good, but only if the switch is attached somewhere (with the provided adhesive for its base). However, when it is freely resting on something else (which is convenient in many cases - for example, I find it convenient to have all four of my switches like that), it is quite difficult to detach the base from the switch! The detachment is done by lightly rotating the base, but it doesn't provide easy grip points (since it can only be held from below and without distinct slots to counter the rotation) while it attaches quite tightly there! Trying to use tools (such as screwdrivers, etc.) as leverage makes it very easy to injure both fingers and the soft gray plastic of the base. Personally, I manage by temporarily and provisionally attaching it somewhere so that I can rotate it there (since the base will be stuck there) and then, after changing the battery, carefully detach the base again to reattach it. I should mention that this "technique" is the same for other Xiaomi devices, such as motion sensors, etc.

Finally... although it is not directly related to this particular product as it mainly concerns the Xiaomi Home app, I think it is necessary to mention that the process of creating or maintaining the "rules" provided for controlling and automating Xiaomi devices through the Xiaomi Home app has become very problematic. For quite some time now, there has been a general issue with the Xiaomi Home app that does not allow this management. In practical terms, it is not possible for someone to create new rules. However, all the (existing) previous rules still work correctly, but it is not possible to create new ones!!! So if someone buys a new device like this and (what's more logical) wants to set up some automation rules for it... practically they won't be able to!!!
They may be able to, but with "tricks" that are completely inconvenient! Tricks like running the Xiaomi Home app from an Android emulator or having the environment of the Xiaomi Home app (e.g. the installation on your phone) set to... German (Deutsch) language (so NOT in English-Greek, anyway, the Xiaomi Home app doesn't even have it)!!! Unbelievable but true 100%!

However, I still recommend it as a choice for purchase and use despite the negatives I have identified.

All these "many" (in the end) for such a small & cheap yet very useful smart peripheral.
I hope I helped some people who are interested in it and may not have known all these details.

* Addition on Wednesday 7/12/2022:
I considered it quite useful to add that -finally- Xiaomi fixed this issue in the (Android) Xiaomi Home app and -oh miracle!- everything seems to be working correctly again regarding the inability to create new rules for its smart devices!!!
I noticed this on my phone after installing its latest update yesterday (on the 7th of the month) and I must say that I was very happy about it because it is an extremely useful feature that had essentially been canceled for quite some time without any official announcement.
Instead of adding this comment, it might have been preferable for some to simply remove the mention I had made and it would be as if I had never made it. However, I judged that on the one hand it would not be very fair if I did it that way and on the other hand it is better for others to know about such "missteps" of the company, even if they were eventually fixed.

Connection in zero time. VERY high-quality plastic, fast response to commands with a nice "click" feeling. It seems like we're stealing from Xiaomi straight up. CAUTION! It ONLY works with a hub. For battery replacement: The sticker is on the base that sticks to the wall. To change the battery, simply turn the body counterclockwise (it requires some force), you will hear a loud "click" and after changing the battery, attach the body to the base with a slight push and turn it right. You will hear another click and you're ready.

Update 1/9/2021: Today, after just a few months, not even 1 year, the long press of one of the 6 switches stopped working. I thought it was a battery issue. I changed the battery but then the switch stopped working altogether. I tried 3 different compatible batteries, obviously CR2032 3V, but nothing. For some reason, it does NOT work if you change the battery. I put the old one back and it works except for the long press. I deduct 2 stars, so we go from 5 to 3. For the money, almost 8 months... not even close!

Update 10/9/2021: The switch works again on long press. It was actually a software issue. Many bugs in the past few days. Magnets disconnect, buttons stop working... I keep the 3 stars as a punishment and we'll see!

Update 26/10/2021: Whatever, Xiaomi. The switches work whenever they want, not whenever they should. Their sensitivity has also changed. Long press and double press still don't work. Let's move towards getting rid of them. I'm tired!

Update 31/1/2022: I started transitioning to the Tuya ecosystem with switches and bulbs from various brands. This particular Xiaomi switch is excellent in terms of construction and at a good price when you get it for under 10 euros, but Xiaomi is very tiring with the occasional bugs and server crashes. Another reason to switch to Tuya, which is preparing an update for Home Assistant that will work without the internet.