bouncing to mp3 or aiff

[plasticefx1]

hey everyone, i'm new here but have had pro tools since my 6.4 le on my old ibook running 10.3.2. i'm now upgraded to le 7.0 (and wondering if i should upgrade to 7.1), all running on a new powerbook g4 1.67, running ox 10.4.3. (tiger). my question is...should i bounce tracks as aiff files or as mp3 files. (i get messages that in order to bounce as mp3 files i need to upgrade 7.0 as well to allow me to bounce mp3 files). it's not a big deal cause i can bounce as aiff files then add to my itunes library and convert from aiff to mp3 there. which is better to bounce as, aiff or mp3? i've had no problems in the past but now i'm having trouble bouncing old pro-tools tracks i recorded in 6.4 le as aiff files. i have 1 gig of ram installed so i should be screaming. working off an 80 gig harddrive as well. help!!

thx..

plasticefx

(i have to open pro tools 7.0, pull up an old pro tools file from the old 6.4 le recordings, then bounce to my harddrive, then pull into itunes and THEN convert to an mp3 in order to save my old pro tools le 6.4 recordings as new itunes files. help!! also...when i burn to cd, the pro-tools sessions tend to clip, whereas regularly burned store bought cd dont. and i lowered the burn speed to 20x. ok....thanks!!!