Hi! Before of all sorry my poor english, I'm Spanish...
After spend all the day trying my amps/cabs in all possible combination I tought that I can contribute to the forum writing my opinion. The test it's absolutelly subjective (only my ears ).
Ok let's go. This are the things I have: Scroeder 1212l, Phil Jones 12b, Phil Jones Super Flightcase, Markbass F1, Markbass MiniCMD121, Markbass NY 121.
-Scroeder 1212l (4 Ohms) & Markbass F1:
The loudest combination. The punchiest sound to me, poor low end (sounds better in the mix than alone), not well defined midrange ( with his famous low-mids bump) and loud and crisp high end.
-Phil Jones 12B & Markbass F1:
It sounds lower in volume (it's 6Ohms and less efficient), but I think farts out at lower volume than the scroeder (maybe cutting some lows and boosting mid lows can compete more in volume). It's the best bass sound that I never heard. A lot of lows, very clean mids and superb highs at any volume. It looses a bit definition in the mix when run the amp flat versus the Scroeder.
-Markbass MiniCMD121 & NY 121:
Very good lows and mids, but the highs are too edgy for me, the little tweeters don't like much. If you not are in slap/tapping the overall soun it's very good, more lows and more refined than the Schroeder, and close in volume. When play in pubs, I have always problems with boomy lows coming from the rear ports if it's close to a wall.
-Markbass MiniCMD121 & Phil Jones Super Flightcase:
Very good sounding combination, tight and defined lows, punchy mids (type scrhoeder), but very much pleasant high end. This strange combination is the most versatile for me, cause I can use the pre of the markbass or the flightcase, I can regulate the volume of each amp, and I can EQ each one independently.
-Superflightcase on top of the 12B-F1:
Amazing sound, like the 12B alone, but more volume, specially on the mids-highs. You can hurt your ears with this slapping thunder machine.
In resume. I think the most versatile combination is the flightcase with the Markbass, and if one amp dies in the show, you still have another (it's not very common', but I had this problem almost four times in the last two years).
If you have any question.... I hope this will help someone!!!!