Both were great but different. Jodeci had a grittier image and a darker vibe, and their lyrics were boldly sexual instead of subtly sexual. At that time it was shocking because society as a whole was outwardly conservative. Musically and sonically, they were disruptive and innovative as they deliberately broke with the traditions of the past. Their production was fresh. Compared to B2M, they occupied a alternative lane in music. They incorporated hip hop elements into their music. They were the pioneers of modern Rnb (jagged edge, b2k, usher, Chris brown, trey songz, even the weekend )They mostly appealed to young black folks though.
Boyz II Men had much more crossover appeal than Jodeci. Great voices, great vocalists and clean cut image. They were relatable enough for Brehs and were safe enough for cacs, their music appealed to everyone, to every generation and every race. They had a bubble gum pop mainstream friendly sound with politically correct lyrics. They sang about sex and love in such a subtle and inoffensive way. The production/songwriting was excellent but polished and Saccharine. The music itself wasn’t truly groundbreaking/innovative but it was definitely catchy. Their Melodies were earworms, they stuck in your head forever.