Yes, the SS3601/3602's are also good but I prefer the V6 Vivids over them by a small amount. The SS3601/3602's are clearer sounding with the impression of slightly more detail, but that is mostly because they lean the sound out more compared to the V6's. The 3601/3602's also push the stage out a little, and have reduced dynamics compared to the V6. The V6's are more realistic IMO, but overall both are close enough that it's going to come down to preference.
That said, the SS2590 & SI 992/994's are a big leap over the others in sound quality. The SS2590's are better across the entire range compared to the SS3601/3602's. My entirely subjective ranking would be:
1) Sparkos SS2590
2) SI 992/994
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3) Burson V6 Vivid
4) Sparkos 3601/3602
5) Burson V6 Classic. These would be #3 but the staging is too close for my preference compared to the more accurate Vivids.
Both #1 and #2 are larger op amps though, and won't fit in many applications. If the V7's can bridge the gap between the V6 Vivids and SI 992/994's, then that will be a huge deal to me since the V7's have a much smaller form factor.