Hi all, sorry to ressurect this thread. I recently downsized my rig from a GK 4x10/1x15 stack to a Roland D-Bass 2x10/115x. I've had it for a few months now and my general consensus is positive.
My opinions, if anyone cares (

) are as follows:
lunkfur's opinions are pretty much shared by me, though I find the COSM models to be all blessings and no curses. The Super Flat is by far my favorite for use with my G&L 2500. The "expander" button is usually on, but if I'm just playing at home then I have it off. I dig super low lows, and the D-bass can make that happen.
The Vintage COSM model sucks a lot of treble out, which works great with my Ibanez SR506 with active Bartolini MK-1s. It smooths the entire spectrum of sound out and gives it a much more traditional quality without sacrificing dynamics or musicality.
My least favorite is the Modern, as it sucks the midrange out and is sort of an "Instant Fieldy" setting. Treble is boosted, as is bass. It's clear it was meant for slap bass or pickstyle, both of which I do not do. I enjoy it with my ash-bodied P/J Aria, which has a very scooped sound by default.
The compressor/tube compressor is nice. I have the tube option on pretty much all the time, at about 25% compression. It has a very solid tube emulation that has replaced my SansAmp BDDI.
The EQ, I must admit that I don't touch it aside from turning some mids down when I use the Vintage setting. I never use the EQ on my amps as I've always found that it does not give me the tone I want any more then if I don't use it. Either the bass sounds good direct or it does not sound good at all IME.
As for live, the 210 combo DOES have some balls, and is more then ample for practice. I use the 115x extension cabinet (which is the same rig as Alain Caron!) when I do live shows, as it's always good to have another 300w pushing a 15" when you've got a big room to fill.
It's impossible to explain the settings on the amp in detail without going on for boring hours, so I'll make it rather quick: The Roland sounds GREAT. The power is there. It is light (so deliciously light after my 300 lbs of GK cabs), and I have banged it around a bit, but it has held up. If you don't get the input stage correct (active/passive and gain) then there will be a lot of hiss from the compressor, but this is easily remedied. If you use an active bass, the active switch should be down. Its not just a Gain modifier, it actually treats the input differently. If using a passive, then make sure it's off. This will increase your sound quality quite a bit. Its a light, incredibly responsive and incredibly good sounding 2x10. I went into GC the other day and was blown away by how muddy and unimpressive all of their amps and cabs were after spending time with the Roland. It spoiled me.