Since I've had my V, I've been slowly letting go of the notion of using a boost/OD along with the gain channels, at least for rhythm sounds.
I haven't found ANY pedals I like in the Vs loop, I'd experiment more with the loop, but I use a switcher out front that controls the v and all my pedals in loops and I prefer that versatility.
On the the pedal board I use with the V, I'm only running an older MXR Zakk Wylde for OD, I use in my lead settings with the Vs Solo function, I have a Ch3 rhythm preset that includes the OD but I haven't been hitting all that often. I need CH1 to be clean when I use it so no OD there, and I don't find it necessary anytime I use Ch2.
The ZW pedal is pretty much the only OD/Boost I've held on to, I've tried: Seymour Duncan Pickup Boost, EHX LB-1, EP Booster, BBE Sonic Maximizer, TS-808, OCD v4 in all situations and although I love all the other pedals for what they do on other ams (except the OCD) - I didn't like them with the V. I've been selling off a lot of pedals this year.
I don't think I'm finished yet, I'd like to try a BB boost and a Soul Food. But I'm in no hurry.
I find the MXR Carbon Copy and a newish MXR Phase 90 to be incredible for what they do in front of the V, I use them individually in presets with the solo function, and the ZW OD, an Xotic SP Compressor and an MXR 10 band EQ (to counter the "V" in the amp's EQ) for leads. I love theseveasy to find "cheap" pedals with the V.