I have had the vacuum for 2 years!
For €300 at the time of purchase, I might say it’s not worth it, unfortunately! For what it offers, it doesn’t justify the price. With the same money, you can get a Xiaomi, which I personally saw is more "thought out" from the bottom side of the vacuum.
Also, Viomi does not have representation in Greece, so if something goes wrong, you will have a problem (like I did) with the warranty as it may need to be sent abroad.
Overall, a lot of hassle and zero support.
Observations:
It cleans quite well the dirt to the point that the bin fills up on the first go, so it needs to be emptied immediately. The other downside is that there is no notification for when the bin is full. The problem: I had it set to vacuum and noticed that half the house was as it was before, and I saw that even though the bin was full, it continued to vacuum. I find it completely ridiculous that the bin fills up within the first 10 minutes and it keeps vacuuming without a sensor to notify you. And for a €300 vacuum, yes, I would expect something like that.
So, a very small bin which does "not" serve its purpose.
Mopping is satisfactory.
Finally, with the first vacuum, as well as the second one that came due to the malfunction of the first, I concluded that the sensors it has are not that good-smart. The vacuum keeps bumping into objects, resulting in it getting marks over time, and gradually the sensors themselves are getting scratched as well.
That’s all from me. 2/5!

The best thing I have ever bought.... I haven't had to deal with the floor for a month and a half.

Initially, it is amazing for sweeping, it has a lot of power, easily goes on carpets and leaves nothing on the floor. The only issue is with carpets that have long hair, which is a problem even with a regular vacuum cleaner, but you can create a virtual wall around those specific carpets and you're good to go. Be careful with cables like headphones and chargers because they can get tangled in the brushes and wheels, and it can be a hassle to remove them.

For mopping, it does a great job with the Y-mode function. Just to test it out, I left ketchup to dry on the tiles and it completely removed it. During winter, you need to set up virtual walls around the carpets, which is easily done through the app. Personally, I have set it up to create two maps for winter, one map for sweeping with virtual walls only on carpets with long hair, and another map for mopping with virtual walls where there is carpet.

In terms of maintenance, it is easy and quick, you can be done in 5 minutes.

Overall, it is a very good vacuum cleaner with good software that is worth its price!

Very good! Having had 2 other vacuums in the past, I can have an opinion! It cleans the floor very well and its mopping is very good. I haven't tried the carpet yet, but I will write again once I do!