It is extremely lightweight compared to a regular lead-acid battery and extremely reliable. I have installed it on my scooter for 3 years now and it works perfectly. It provides strong starting power and charges quite quickly (the scooter has a voltmeter and you can see the charging). It requires no maintenance, you install it and forget about it. One disadvantage of lithium batteries is that their performance drops in the cold. On some cold winter days, because I was making short 3-minute trips, it didn't have time to charge properly and, additionally, due to the low temperature, it started having trouble starting. However, after a half-hour ride, it fully recovered. The other obvious drawback is that it costs twice as much as a regular battery, but I think the investment is worth it and in the long run it pays for itself.
Edit: The battery is already reaching 6 years on the scooter and still works perfectly!
Edit_2: After almost 8 years, the scooter is struggling to start, so it's probably time for a replacement. But it was worth every penny.

I installed it in September 2018 on my 2009 X MAX 250 cc model. So far (29/1/2019), it's working great! I was frustrated with other batteries... they needed to be replaced almost every year. The only downside is that it requires a special charger for lithium batteries. However, it comes fully charged from the store. You can install it immediately. I will see how it performs in the cold and update...
P.S. It's now April 2019, and the first winter has passed without any issues.
Edit 1: January 2021, the battery is still holding up! This winter, due to the coronavirus and not using it much because it has an alarm, the battery drains in 4-5 days. But I have bought a charger suitable for this battery and have charged it about 6-7 times without any problems.
Edit 2: January 2022, the battery has significantly dropped in performance, and with the cold weather, on the second day of immobility, it failed to start. When I took it to the electrician, they told me it needs to be replaced. So, I replaced it with a gel-type battery... I have it charged at home just in case. It lasted well for 3 years.