LaserActive. Just because you can have SEGA and PCE in a single unit, and everything is front loading so it's a lot easier to stick in a media cabinet and go and play. LD playback is okay, but the real benefit is having something that does 2 systems in one nice box.
Laseractive is sexy, but I can't justify the cost.
I went the briefcase route and have no big regrets. Did take me awhile to find a working CDROM2 in original condition though. I really like how it looks together with the original white PCE unit. The main thing that does suck is the cost difference in arcade cards. However, I'm not missing a ton there, so I'm not getting an arcade card pro any time soon.