We have HS200 switches in various places around the house, and they're great! Just be sure your existing wiring has the white 'neutral' wire before ordering. Most houses built in the last 30 years or so should have this, but it doesn't hurt to double check it before ordering switches you can't use. Other than that, installation is a breeze, and connecting to your WiFi is simple with the Kasa app on your phone.
I have seen others asking about fan control with these switches - we've had a switch on our bedroom fan for over a year now, and it works great! Zero issues with the fan, other than you can't change speeds with it - you have to use the pull chain on the actual fan to change speeds. We leave ours on high all the time, so it's not a big deal for us. Being able to turn the fan on or off in the middle of the night without getting up is a game changer!
We initially went with TP-Link because they use WiFi and don't require a hub. We eventually got a SmartThings hub to control our front door deadbolt, and there are 3rd party addons that will allow all of your TP-Link switches and things to be managed in SmartThings. Other than the initial device setup when we add a switch, I never have to use Kasa. It's a fine app, but having to control my Z-Wave stuff in SmartThings and TP-Link things in Kasa got old. This brings all device control into one app, which I love.
Controlling any TP-Link switches, outlets, or bulbs with Alexa is a breeze to set up as well, and very handy. Never had any issues with this, and it's super convenient to tell Alexa to turn on the lights when you walk in a room with your hands full, or tell Alexa to make sure everything is off when leaving the house.
My only complaint in about 2 years of using these switches was when our old wireless router died - I replaced the router and even though I used the same SSID, password, and authentication type on the new router, the switches couldn't seem to connect to it. My only choice was to go around and hard reset every switch, then reconnect them to the new network. We have about 8 HS200's scattered around the house, and it only took a minute or two per switch, so it wasn't a big deal. I knew that I would probably have to do this, but was hoping that with the new network set up exactly the same, that they might just jump on and do okay.
All in all, these are fantastic switches, and I have zero complaints with them. I'm looking at getting some of the newer 3-way switches for my hall lights, and also thinking about switching some of our light switches to the HS220 dimmers, but we don't have dimmable LEDs yet, so that's a project for another time.