Hey,
I've just found this topic.
I have the T-bone RB500 since december 2005. (133€ then)
I've bought a pair to use them mainly on drums as overheads. They sounds really great.
Also, I tried them on acoustic guitars... and I got this little hiss...
Low output mic.
It needs a great preamp. I use a SPL Goldmike to plug both RB500.
Better than using the Motu Travelers one but it could be even better...with another preamp...and with another mics too!!!
I love this sound. I may have a look at the stereo mic from cascade (ribbon).
Maybe this might be even better than the RB500.