Yes they require a controller.
IAP model have an integrated peer to peer controller.
look on ebay and you can find real bargain like IAP-135 has 3x3 antenna and dual band (no AC speed) and you can find'em used for 30 bucks (usually without AC adapter because most of installations uses poe switch) that someone try to sell new for 900 dollars...
Compared to cousumer AP... well there is no comparison...
There are two variants... IAP-xxx-US and IAP-xxx-RW (and IAP-xxx-JP). You cannot mix these together in a cluster, as one is only for US (FCC only certified) and the RW model is for Canada, EU. You *can* use a -US version in Canada, but if you hook it up to Cloud Central it may not continue to work. Best not to hook it up to Cloud Central if you do that.
The IAP-225 is EOS, and support goes for another 5 years. If you want to future proof, stick to a IAP-3xx series. I would personally avoid the 305 series. The 2.4GHz is speed limited.
And yes, you will need a POE+ switch to run these unless you can find the adapters, which is not as easy as it sounds. They *will* work with regular POE, but two 2.4GHz antennas will be shut down.
I spent about 600$ US for 3 IAP's last fall, well worth it, as the WiFi just works, where before with my Ubquiti I would get strange disconnect and speed errors from some IoT devices I have.