Anything Milt Sparks makes is going to be an extremely well made product with quality through and through. I’ve worn both the holsters you mentioned and, although both good, neither is my preference. I think the best Sparks IWB is still the original Summer Special..... not SS2.
The VM2 was always far too bulky for me with too much material necessitated by its design. Although very effective and concealable the VM2 was too uncomfortable for me and sat much too low in the waistband for my tastes.
The Summer Special 2 is somewhat close to the Summer Special except has the addition of a body protector, removable belt loops, and, like the VM2, the SS2 has a lower ride than the S/S.
I’ve always felt that the original Summer Special (or the current iteration thereof) is still on the cutting edge of IWBs and possibly the best there has ever been. The Summer Special’s simple design is what allows it to be so effective and still so popular to this day. It’s a workhorse of a holster that is essentially an open top “gun bucket” making drawing an reholstering effortless and, with no body protectors, retention straps, or the like to inhibit it’s effectiveness, it doesn‘t give up any speed or accessibility to OWB holsters. Bruce Nelson sure knew what he was doing when he stitched together the first Summer Special!!