I've installed two. One on my dad's 33 gallon, no complaints of it failing and it has been on for 4 or 5 years now probably only getting used a couple dozen times a year.
The other on my 26 gallon which I had issues with the plastic line shooting out of the compression fitting. Once I got that squared away, it was fine the few times I used it before upgrading to a 60 gallon.
I did read that if you put the plastic line too close to the compressor, it will heat up and the line will fail prematurely due to heat/melting.
A good idea I saw on the net somewhere was to use a ball valve and plumbing fittings on the release valve on the bottom. Then just go over and open it at the end of each session to let the water out. I do not know if this needs to be a special ball valve for handling air instead of water, but seems like a sound idea.
I have had one of these on my 60 gal CH/Husky compressor for a few years. I've seen a few problems. The first problem is that the pneumatic "motor" that operates the autodrain uses a really thin rubber membrane to actuate the release valve. small ammounts of rust from the tank eventually caused the mechanism and membrane to fail. You might prevent this by cleaning it out periodically and probably lubricating it. My solution was to buy a replacement kit (actually a few replacement kits for spares).
I also had the cheapo plastic tube going back to the unloader valve melt on the first use. I replaced this with some copper tubing. Unfortunately I can't get the original nicer plastic tube from CH/Husky off of the four way pressure switch to replace it with copper so I have a jimmied up configuration there.
If anyone knows how to get that fitting off I would really appreciate the info

I'm afraid to try and force it off because the four way switch deal is pretty expensive.
The auto drain seems to not always get all of the water out so I also have a 1/4 turn valve on the drain to check/fully flush manually. I don't know if I would do it over again. My fear was that it would run at the end of the day on say sunday while using it and cool down overnight and have water sitting in it for a few weeks until I used it again. I thought the auto drain would do a better job of clearing the water. I'm committed now with my unloader hose cut, so I am leaving it in.
I guess it gets a barely pass.