The Icemaster Maxx 4 is what I use. There was definitely a learning curve with it.
Overall impression - I do like it. it works as advertised. Couple of the cons I can think of are it's loud (comparable to an old, rattling AC window unit), the instructions are absolutely horrible (or lack there of), and power outages were a fun learning curve.
It works great though. I have mine sitting at -3*C and can cold crash 15g to 34*F no problem at all.
The quick disconnects are priceless in my opinion. When a batch is done, with a simple push of a button, I can disconnect the largest portion of the hose from the fermenter and all I'm left with are the little 6" leads that I have attached to the cooling coil. Would definitely recommend the quick disconnects.
In regards to what size hoses are required, I'd have to go back and look. I want to say like 1/4" or 5/16" ID tubing... Not 100% sure on that though.