well, there are 2 different arcs...ls and aaa.
first off, whether or not you are asking...you
do want a aaa. just get one.
good, now that we have that cleared up
...
the arc ls (i am assuming this is the model you were refering to) is indeed brighter than the mini.
i don't own any un-modded mini's right now, so i don't know the battery life. the ls, however, is semi-regulated, meaning that it will stay at constant brightness for a while, then eventually loose brightness gradually.
if you want the brigthest and blemish-freeist, then you will want to get a premium. premiums depend mainly of availability, so if you se one (lsh or lsl, i will get to that in a minute) it would be a good idea to
pounce.
ok, now about lsl and lsh. lsl means that is uses a low-dome emmitter, this will yeild better results for close up work, and will feature a rounder beam than the lsh (ls high-dome) will. the lsh will reach a bit farther, but will appear to have a slight "star" shaped pattern, some like this, others don't, some just don't care.
personally, i would get an lsl premium, but if a lsh premium were available sooner, i suppose i would get that. (i prefer the rounder beam).
lsh's might also have a tendancy to be slightly whiter than the lsl's, but at the premium level, all will be pretty white and pretty bright.
if you're looking for the best to start out with, i suggest you get the ls. (you can always get other flashlights afterwards
)
***edit*** i see sunspot budged in line...oh well. he also brings up the conversions for the mini, these are good also (i recommend either dat2zips or intretechs (or both) drop-ins being as you are looking for brightness, the opelec will give you a long run-time, but you said bright. (bright is good
)