I got Viomi S9 last week. I was planning to get Ozmo T8; however, I decided against it at the last minute. The seller has increased the price from 43k to 51k in the previous two weeks, and many recent reviews mentioned issues with the fall sensor.
Here are my preliminary observations of Viomi S9:
I bought it for 42.5k, including 5% Amazon cashback.
It uses LIDAR-based navigation, so it doesn't bump into furniture and objects. However, it can get stuck on wires and small items if they get caught under the wheels. I have a three-year-old, so I remove all toys and small things from the floor before using the robot.
The suction power is good; however, it gets loud on the max setting. It is not good at cleaning corner and boundaries. There is a dedicated mode in the app for cleaning edges. It helps a bit but doesn't solve the whole problem.
It comes fitted with an intelligent water tank that has three preset levels for water dispensing. Mopping is okayish. It cannot remove tough stains. It would be too much to expect this from a robot vacuum cleaner. My maid can't even clean those stains properly.
It is also equipped with an automatic dirt disposal system where all the dirt from the robot gets sucked into the charging stand, which uses a disposable bag. It happens once the cleaning is complete; however, the process is a bit loud and lasts 10 seconds. As per the website, the disposable bag can last one month. So, it is an additional expense, with each bag costing around 150 bucks.
The battery capacity is 5200 mAh. It takes about 5.5 hours to charge from 10% to 100%. I am unsure whether it is on the higher or lower side as this is my first robot vacuum.
It takes ~90 minutes and drains ~50% of the charge for cleaning an area of ~1000 sq ft. I use a Y-shaped mopping pattern, which is slightly slower than the S-shaped pattern but more effective.
Overall I am satisfied with the robot as I was aware of some of its limitations before the purchase. I expect it to reduce my daily chore workload, and I can do a deep clean every 7 or 10 days with a regular vacuum cleaner.