I've been using two 12" cabs with a LMK2 head for over a year now, have thoroughly enjoyed them, and plan to hold onto them indefinately. For me they have a clear voice that have articulated every note I've attempted to good effect. Cabs are like strings, there's no best or worst, just the ones you like the sound of.
Their lack of weight has become the norm rather than the exception for me, I could never go back to struggling with a heavy cab now. Aesthetically I think they look quite tidy, but looks aren't a dealbreaker to me, and I'm sure they wouldn't be to everybodys taste. I wouldn't describe them as lacking in volume by any stretch of the imagination, I'm sure there must be louder cabs out there, but then I'm not interested in chasing that particular sonic prize.
There's only one way to find out if they're the right cabs for you, and that's to try them.