In general, I personally find that the MK4V and MK4 to have quite different personalities and sounds. While I understand frequency graphs, I generally don't rely on them at all because they just don't tell you what your ears do. The 4V is a bit brighter, but also a bit tighter, slightly less warm but with a bit greater detail on the low end. In general, my opinion is that if you tend to like low end, the MK4 would be the choice where if you tend to like high end, then the 4V delivers a little better there. IMHO, for some reason, there's some pre-amps that causes the MK4 to sound like crap (muddy). However, given the right gear combo, I prefer the sound of the MK4 to the MK4V. The 4V probably has an overall better neutral balanced sound across the spectrum...I think DSatz said that one of the main reasons Schoeps introduced the 4V was in response to demand from customers that complained that the MK4 was bassy, but of course, being a rock 'n' roll junkie, I love feeling the floor shake and I love the feel of the bass massaging my internal organs.
In terms of end address vs. side address, I'm not sure I care one way or the other. It seems like I can isolate a sound source a little better using the end address capsule. The reason I say this is that I sometimes tape in a fairly boomy place here in Pittsburgh and with the MK4, seems like there's less reflective sound when pointing the MK4 straight at the speakers than doing the same with the side address capsules. The side address caps do give you greater flexibility than end address in mic positioning...IOW, the end of the mic can be positioned pointing up, sideways or down as long as the cage is pointing forward. The side address capsule can also be handy for stealthy recording...I once recorded a public performance in Japan and didn't know how to ask if it was OK to record, so I had all of my gear in my backpack and simply stuck the ends of the mics sideways out either side of the pack...with cage facing forward.