I've used a really old Black and Decker at the office and it was fine, but the owner of it said the newer ones weren't nearly as good.
I had a Krups unit at home and it was AWFUL. Set it on fire because the dial made me think the opposite end was pointing to my temperature - very hard to tell what it was pointing to.
Replaced it with a DeLonghi convection toaster oven with digital display. We LOVE it.
I can't believe you're not interested in convection, it is SO great! Best/easiest way to roast peppers (or other veggies).
I make tacquitos where I just fried the tortilla for a few seconds, rolled and froze, the convection heats them up and perfectly crisps the tortilla, no need for deep frying!
I would miss that convection so much if I replaced this unit with a standard unit.
Still, I'd say most important is:
Easy to use - very easy to see what temperature you are using.
Acceptable temperature range.
Auto shut-off (but they probably all have that by now).
Size - bigger will take more space and more time to heat, but you can do more in it... A medium sized one is probably fine though.
Frankly, I bought mine online. Much local research had prompted that Krups buy (which was so horrible, and died before the warranty ended but was so horrible we didn't even want it fixed under warranty).
Seems most best kitchen stuff I have I researched and bought online.
Good luck!
Nancy