funny that ovals are the weakest biner and everyone is recommending using them for a carabiner "break"
you dont need multi biners to rappel if you have 2 angle pins you can make em into a brake bar, caver style rappel device with a locking biner, good enough to get you down.
in summary:
ovals Heavy, weak, still better for some purposes some of the time, retro fashion statement. go well with an elbow-deep chalkbag and some EB's worn with stripy tube socks so that you look like a smoot photo.