I've now tried the A20, QC15/Uflymike combo, Clarity Aloft, Quiet Tech Halo, Sennehiser HMEC-26 and DC Pro X. All worked well.
The A20 is giant, gets hot on long legs and is a pain to carry. The mic gain is way too high and keeps the CRJ intercom on with background noise at all times. On the good side, it is the quietest out of the ANR sets I've used, and the music input that cuts out with ATC is nice. I returned the A20 after a 4 day.
QC15/Uflymike is 95% of the noise cancellation, and much smaller, comfortable, and not as hot as the A20. It also has a screw to adjust the Mic gain which is awesome since you can adjust it to cut out completely when you aren't talking, makes the cockpit much quieter. Music input sucks since it's up on the mic itself, and unless you get the TSO version and also wear a set of earbuds, it dies when the battery in the Bose dies. Some airlines might not let you use it if you don't have the TSO version. I had one check airman who had a vendetta against people using this combo and only let me use it when I put the ear buds in.
DC Pro-X I flew one leg with. CA I was flying with picked them up at the Stopover Store in the middle of a trip, didn't like them and let me try them on the next leg. I liked them. Fit well, felt a lot like my QC15. Not quite as quiet as the QC15, great mic on it. Look very cool.
Sennheiser - I've owned these for nearly 20 years and flight instructed with them etc. Very light and comfortable, not as quiet as any of the others, but mine are an old model, they've probably advanced since then. By far the most comfortable of the normal style headsets I've owned. They are more and on-ear style like the DC Pro X than an over the ear like the QC 15 and A20, so they have a different feel and are not hot. I also wear glasses, and they are by far the most comfortable of the normal headsets when wearing glasses, and the glasses don't break the noise seal like the A20 and QC15.
Quiet Tech Halo - Bought these about a month ago and returned them right after the trip. The Mic gain is way too high and super loud, can only be adjusted by sending them back to manufacturer. They are good with glasses since they don't depend on a seal around your ears. I could never find a great way to wear them that was comfortable. The part that goes over your right ear is thick and created pressure. You can wear them a bunch of different ways but I was never able to find on that was really good for me. They do sound great, and the music input is very good as well but doesn't cut out with transmissions. Not TSO, so might not be legal to use at your airline. Great price.
Clarity Aloft - Overall my favorite. Flown with them as my main set for 5 years and thousands of hours. Very comfortable for me, even on 4 hour legs. For me more comfortable than the Halo since both sides are very slim rubber coated wire and is great with glasses. Sounds great, very quiet just like a set of ear plugs. Mic gain not adjustable, but comes set at a good level that cuts out the intercom when not talking. Music input is down on the control box but does not cut out with transmissions. I only use one ear when I have a jumpseater so I can talk to him/her and still monitor ATC. Mine is the TSO version so it is legal at any airline. Downsides are that it and the ear tips are expensive. It works with any Etymotic ear tip though, and they can be bought cheap on Amazon. The control box on mine also broke after about 4 years. I was quoted $100 to repair it, when I sent it in they ended up fixing it for free and sending it back after completely refurbishing it with a new box, wires, etc etc etc. I also like not having batteries.
Hopefully that'll help you, they were all used in the I used the QC15 and Clarity Aloft in the 200 and 900, Halo only in the 900, and the others in the 200.