I play bluegrass and oldie tymie fiddle music with the band I'll be playing the bass with. So now I see no need for fancy tube amps. I play blues and country jamgrass with the other band I play with and drool over the other guys i play with fender tube amps. They just sound sooo sweet and was looking for an excuse to get one too.
Neddyrow,
Since you aren't competing with a drummer I'd say the MB200 paired with the MBX is a real nice combo that's really lightweight. Going FOH to the P.A. is fine for the audience but unless you have a very sophisticated monitor set up with individual sends (which usually isn't the case) it's nice to have something on the stage to hear the bass. I like the portability and sound quality of the MB200 and you can always add a different cabinet later on if you go with a head/cabinet setup. Clink has the right idea.