i had a problem with the mobilepre as well. bought it used from a member of this forum, installed the drivers on my laptop (new dell d800, with usb 2.0), and the damn thing kept bluescreening my laptop.
i'm a systems engineer by trade, so analyzing a memory dump is second nature to me, and it was definitely the mobilepre's driver that was at fault. no mistaking it when windbg points directly at a dll.
i brought this to maudio's tech's knowledge, and we went through all the hoops--uninstalling, reinstalling, downgrading the driver, upgrading the driver, all to no avail. then they tried to blame it on my usb2 port, saying it was really a "usb hub" (bullshit).
so i punted figuring it was just incompatible with my system and sold it to another member of this forum, stating my issues with it on my laptop up front. he understood, bought it anyway, and lo and behold ended up having the same problems. thankfully no one had ever filled out the registration card, so he at least had that avenue to go down. i don't know how that ever turned out. i did feel bad for having passed on my problem, but at the same time, i WAS up front about what it was doing to my machine and i DID think that it was just that the driver was incompatible with my machine....so.....
haven't tried the tascam, and i'm really looking at
the maudio firewire 410, b/c it's what i wanted in the first place. i had real issues with the lack of LED signal monitoring on the mobilepre, as well.
i've got an audiophile 2496 and a delta 1010 installed in my desktop machine downstairs and run them together with no problems at all for 10 tracks of audio, so prior to the mobilepre issues, i HAD been very thrilled with everything from maudio.
YMMV,
wade