I can't imagine using the clarity aloft headset in a GA plane. I thought it was too loud in an RJ. As far as the QC15 is concerned, it's the better of the two, but don't bother with the TSO'd version. The only difference is that the TSO'd version has earbuds (that go under the headset) to provide audio in the event your battery dies.

Honestly, I'd pickup a pair of the A20 bose with their 0% financing. $100 a month for 12 months. Your ears will thank you.

Oh, and full disclosure, I have the A20 now and I love it.

If you are considering the Aviation X headset from Bose, you could pick up a used pair and buy new earcups/headband pad/mic cover for cheap from bose and have a virtually new headset that is 90% of the A20 performance. The only downside is the X is less comfortable than the A20 and would not have a warranty like the A20 does.