For the past few months, Ive been rehearsing and gigging with a Mesa/Boogie Bass 400 (KT-88's) and a Goliath III 4x10/Mesa Powerhouse 4x10 cabinet setup. When I was using 6L6 tubes, even at pretty high volumes, the cabinets were being pushed pretty minimally, and sounded great mixed. However, now that I have a lot more power with this head I am finding that at gig volume, the Goliath III is getting pushed to the point where you start noticing its lack of heavy low end. I was plugged into just my Mesa cabinet this afternoon and fell in love with the tone all over again. Since the G-III is a lot more efficient than the Powerhouse, that tends to be what you hear more, but the Mesa tone is what I really like. I still like this setup, but am starting to consider two alternatives- Trade/sell off G-III, pick up another Mesa cabinet. Sell off G-III and other cabs I have, pick up one of the larger Schroeder cabinets as a standalone. Supposedly Schroeders make all your dreams come true.
It really depends on your style, but I just can't get past the 15" sound myself. Have you been thinking down these lines?
If the mesa cab is loud enough alone, than compare it to the schroeder, and see which tone you like best,and go with that one. If you need more voume from the mesa and prefere the mesa cab than trade the g3 for another mesa cab, but if it's ample in volume, than sell the g3 and buy some weed and practice. If you must have only 1 cab and no other cuts it in the volume dept., or if you just preffer the tone, than the schroeder is your next purchase.
I used two 1x15's in the past and dug it, and some other combinations (4x10/1x15, 1x15/2x10, 2x15 with a few different brands). However, the 8x10 wall of sound is my favorite out of everything I've tried. For my niche of music, well-defined low mids are a priority.