I just got linked to this thread, cross-posting from my other post where I was asking about combo amps that didn't suck.
Success post below:
Hot damn, y'all nailed it. I hated the Rumbles. I wasn't able to try a Rumble 500 but the 15" speaker and 12" speaker models sounded anemic to me. I tried the new Ampeg RocketBass line and was able to coax out a sound I liked but it was solidly meh. My favorite model was the 12" speaker. I liked it WAY more than the 15" model. I spent probably 45 minutes playing every model of Rumble and RocketBass while the Guitar Center employee spent ages trying to find the MarkBass 121p that wasn't on the floor but showed as in stock on their website.
I just came home with a MarkBass 121p and it THUMPS! ~25 lbs, 300 watts. For home, I'm finally getting that super low fundamental I was missing from the smaller amps. I A/B'd my Roland MicroCube with the MarkBass and it was hilarious. I realize it's a full-on Class D head tucked inside a purpose-built cab instead of a "true" combo or whatever but this is what I wanted. If Mesa or someone else made a cab with a small slot for a Class D head I feel like there might be a market for it. Until then, MarkBass is the only manufacturer I've seen that does this.
This is exactly what I wanted. Didn't know it existed. Haven't had a combo amp in 10+ years and it's so frickin nice walking to the car with the amp in one hand and bass in another. Going to try it with my Mesa 1x15 or 2x10 at practice this week. @agedhorse I'm guessing either of the Mesa cabs will overpower the MarkBass 1x12. I don't think I'd ever gig it like this but fun to mess around.
Both, but not going to gig with the MarkBass unless it's a VERY small gig. Probably not ever with my VERY loud current band (7 piece, 3 horn players).
For my ears, a big amp turned down sounds WAY WAY WAY better. On the occasion when I have my gigging rig at home it fills me with joy and the neighbors don't mind because I have it turned down. I don't get that same giddyness when playing small amps cranked up.
You sir, had the best opinion. Got the MarkBass on clearance.
gotly, you are living proof that beauty is truly in the eye of the beholder, and congrats on finding the one for you!
The Fender Rumbles have been the industry leader for the past few years and all you have to is take a gander at the Rumble Club’s membership list or its page numbers of posts to know there are many of our brethren who love ‘em. Here in the CC, we have a solid following too.
As for the Rocket Bass series, like with all combos and cabs, it’s crucial to give them time to bloom before you really hear what they can do. We’ve already heard from some new owners that it wasn’t until the first month that the Ampeg’s really came into their own. My 112 was awesome right off the bat, it that can’t be said about all my combos.
If you wanna run your Markbass combo with your big band, add the New York 121 ext cab and you’ll find it to be right on the mix. I used that rig with a decent-sized community band and did fine.
Thanks for posting your great news. Take a pic of your combo and post it here and I’ll pass out a membership number to ya for your effort.
The wife will be pleased!
Making up for the 14hrs silence. 
