Xioami’s Aqara line of zigbee home automation products finally got an official US seller a few months ago: Amazon. 
That’s particularly important because there is an ongoing issue with counterfeits of this brand, so much so that Xioami will not warranty devices bought off of Alibaba. Or eBay.
Anyway, I have a love/hate relationship with this brand. 
I think the engineering quality is very good for their price range, in my personal opinion, better than IKEA’s. And they are very creative in the features that they offer in their different devices. If you read Chinese, it’s a very consumer – friendly brand. If you don’t, you can probably still figure out how to use the individual devices without too much trouble. Of course the prices are great. And if you do use their gateway, the HomeKit integration is a plus.
What I don’t like Is that they are clearly designed only to work with their on Gateway, and consequently they are idiosyncratic when paired to smartthings or echo or other certified Zigbee hubs. They can be difficult to get paired, and hard to keep connected. I also have some security concerns when using their own gateway, although that won’t apply if you’re just buying sensors to use with SmartThings.
All of which is to say I don’t actually recommend this brand for most people. But I do recognize that they are very popular with people looking for budget Zigbee devices. And right now a bunch of the individual pieces are available with a 10% off or 15% off Amazon coupon. (The coupons vary by model.)
Product descriptions will say you need their Gateway, but you don’t if you are connecting them directly to a smartthings hub. However, you won’t get HomeKit compatibility if the sensors are used with SmartThings.
If you are new to this brand, see the discussion thread before buying so you get a feel for the kind of issues that people run into
FAQ: Help! New to smartThings: will Xioami/Aqara sensors work?
