Oh yeah, forgot to reply to the topic:
1)BOSS ODB-3 overdrive
Owned one for a couple of months, it's an *okay* overdrive but it seems to lack a transition from light to moderate OD. Good if you want a distorted sound, but don't expect subtlety or boutique-level cleaning up. Don't push it unless you get it modded, either... if the OD is too high, you get that bag-of-bees sound which may be annoying to you.
2)MXR M-80 D.I+
Tone shaping is not bad but the overdrive is very harsh and unrefined. 3nab has one, maybe you can ask him on how it is for him
3)Tech 21 XXX
Never tried
4)sansamp bass driver DI
I'd rate the tone shaping on this one better than the M80 and the ODB-3. The overdrive was also more natural for me, but I wasn't using it at a very high setting - just to give my bass a little bit of dirt. Liked this one, but sold it because I got the Fulltone
5)Digitech bass driver
Never tried, but I don't have a good impression of Digitech bass products after trying out their bass compressor. Then again, I could be wrong. Your best bet is to actually try one for yourself and see how it performs for your use.
6)fulltone bass driver.
No real tone shaping available on this one (the tone knob is more of a hi-cut knob), but as long as you've got a good enough bass (or a preamp to back it up), your low end will be retained very well. However, it does lose a little low-end when pushed all the way, but nothing you or the crowd would notice when performing. Very natural overdrive, very good overdrive as well! My favourite
