Mark Bass Studio VST

I got it (free) because I was going to review it. I think its ok for clean bass but didn't like it that much overall.
For bass I like to use Amplitube X-Gear combining various amps with cabs and mics. That's only good if you have a couple of Amplitube products.

Alternately I'll plug into my little ampeg amp. :D

I don't think I've tried Markbass with my new bass (stingray)
 
I think it cool for funk/jazz/blues/pop, but for heavier stuff there're better things out
there, especially if you want distortion. They should update it and put sims of their
fx into it and of a few other heads, because I really like their amps, the plugin is more
of a one-trick pony.