The updated Kol looks pretty good, but I think the new Marza looks great - something you really don't want to be on the wrong side of.
I prefer the original Akkan though. The old model seems more detailed and gnarly, eg forward comms / sensor antennae + launch bay and the bits of hull that seem to be welded on extensions.
The old model has that lashed up "civilian ship that's been pressed into emergency military service" look that fits into the early lore of the TEC's first engagements with the Vasari.
Newer version looks a bit too clean, how I imagine the Akkan looked during its, original, civilian role as a passenger liner.