I have the MB4210 and I've been really pleased with it, capable of some great tones. The modern channel is great for slap tones, and the classic has a real grind to it. Be aware the classic channel is quieter than the modern channel, but you can compensate by using the blend facility.
I did try the MB4410 (it's enormous!) but decided the 4210 was more than sufficient for rehearsals, and just bought the 1x15 extension cab to add at gigs.
I know another person on this forum has had reliability issues with theirs, but I haven't had any problems so far (nearly two years).
Final thought: Love mine, but try before you buy because everybody's different.