no, they are not all the same (well maybe in seat belting ability, but not in usability).
Look for 5 or 6 point, never 4 (4 doesn't deal with the biggest issue, submarining)
Always get the wider one (3" from memory), the wider they are, the more comfortable on long runs.
Make sure they have a rotary buckle, much easier to use day to day and in a rush (eg car on fire)
If you can, check the adjusters. Good quality belts/adjusters slide smoothly, cheapies dont and get caught up.