Honestly, I'd say 112 for the simple fact that they maintained being constant with great to mostly good albums unlike the other groups listed here.
112 >>>>>>>>>>>>>>> the rest of them
112 never had a K-Ci, Jojo, or Dave Hollister but they all balanced each other were good production.
Blackstreet were only as great as that 1st Blackstreet album. The second album was alright but those cats needed Dave Hollister. And after that they never got it back together.
Jagged Edge was cool but outside of a couple of their singles, their music was neither here nor there to me though.
I never checked for Next outside of the singles "Butta Love" and "Close".
112 takes this crown in my opinion.