A few quick comments.

Size- I don't know how airline regulations will evolve (probably towards more strict), but we travel a lot and my best general advice is: (i) If you can put up with non-wheeled, stop right here and get one of those. They are 6+ LB lighter and squeeze into tight spaces. (ii) If wheeled, and you'd only travel US domestic, look at 20"-22". (iii) If wheeled and international, look at 18"-20".

IOW, 22" would be aggressive, with most risk of being checked; 20" something of a sweetspot with some risk; 18" the safest bet. One option would be choose an 18" or 19" expandable, but all things equal this might increase the price (however see a very good Travepro option below). Whenever you have the choice, lighter is always better.

Brands- Samsonite and Delsey make too many lines, from very good to pretty bad, so brand name alone doesn't tell much. Both can also offer good quality/value. I am a tad more familiar with Delsey: Fusion uses lower quality material; Breeze short-cuts in construction; but if you can get a Pro, Pilot, or Elite at a good price that's ok. If you buy a size that would never have to be checked, then even Fusion should be fine.

Basically, make sure the material is nylon, and not polyester or pvc which are more vulnerable to cuts or abrasion. Within nylon, don't worry about Denier count; a non-expert can't figure out when one company's 2000+ Denier is better or worse than another's 1000. Marketing departments count on Americans' legendary tendency to be impressed by big numbers, hyperbole and obscure alphabet combinations ("9850 Super GZX").

Price- What you get with a brand like B&R is not only sturdy construction but also a warranty that will repair/replace any damage forever, no matter what caused it. I am a big fan of B&R and own many of their pieces. That said, I also think that you have more flexibility in a carry-on: you can get very good quality from others, only without B&R warranty+service, but with no need to fear that it will fall apart if gate-checked occasionally.

I did a casual check of a few sites and the following constitute a sweetspot at various price levels you might consider-

Travelpro WalkAbout Lite 2 19", $79: http://www.ebags.com/travelpro/walka...?modelid=98672

Travelpro Platinum 5 19" Expandable Rollaboard, $119: http://www.ebags.com/travelpro/plati...?modelid=78532

Pathfinder Revolution XT 3820 20", $139: http://www.altmanluggage.com/pathfinder_3820.php

Briggs & Riley Baseline 18" Carry-On Superlight Upright, $195: http://www.lazarsluggage.com/brriba18casu.html

More research could bring out other and possibly better deals, but these are pretty good, especially #2 and #3. You might also keep an eye on any seasonal or going-out-of-business sales as well as TJ Maxx type stores. Good luck.