both are kick ass regs.... you can't go wrong with either.
check out this article. It shows that both regs perform almost exactly the same. which isn't a surprise since Aqualung owns Apeks.
ScubaLab Special Report: Muscle Regs
**Note: this article was originally in the November 2005 issue of ScubaDiving magzine. (but for some reason i can't find it on their website anymore but found this PDF on another site). But it's one of the few reviews that gives a head to head comparison between some of the higher performing regs.
(Some of the two brands regulators use the same parts. not sure if these two models do or not... but might be.)
I've got the Legend LX and I have no complaints about how the regulator performs. Out of the several regs I've had and several more that I've used/rented/borrowed, etc the Legend LX is prob the highest performing one I've used.
BTW... remember that right now Aqualung has a $100 rebate or something going on... so don't let your dealer "forget" to offer that to you.
hope this helps.
Mike