GV-2 OVF and street shooting
3' is pretty close to be doing 'street', but I'll assume you're using the term loosely
I used to shoot extensively with the GRDIII and an external Voigt., so I've some perspective on the matter.
The OVF was excellent at 6'+, and the GRD allows you to turn off the back LCD and image review off completely - great for minimizing distractions and maximizing battery life. The only thing I missed in that mode was something like the GXR's "Direct" button, where I could see my dialed-in settings on a single press. At 3' or so however, the parallax was bad enough that I gave up on the OVF altogether. I was never able to mentally compensate, and got tired, tired, tired, of seeing pictures that were ever-so-slightly slightly 'off' and had to be cropped.
Finally, I gave up on the OVF altogether for a number of reasons. Since I shoot everything from 3' to inf. I had to continually switch between using an OVF and the LCD, which was a pain. Also, I carry my GRD around in my jacket pocket and on more than one occasion the OVF slipped off and scratched my GRD (putting the OVF and GRD into separate pockets simply increases the hassle of taking a shot - I really wish the GV-2 shipped with a locking pin). Finally, I found that people really noticed the camera when the external Voigt. was mounted. This probably won't be a problem for the GV-2, which is nice and compact (I finally understand why Ricoh engineers designed it that way), but it may or may not be an issue. I now shoot LCD only and carry 2 spare batteries.