Never heard VTL 2.5, but not for lack of trying. Maybe if I was looking for Siegfried I would have had more enthusiastic response from Bea. Used 2.5s (and 5.5s especially) are kinda rare and sell quickly. Should tell you something...
I auditioned Shrimp a few times hoping to use it with my Manley Snappers. It holds the Snappers back with rolled off highs, flatter dynamics and narrow/flat soundstage. Too bad, because it has great potential with a superb design and very good construction quality and good company to stand behind it. I am tempted to think I heard a bum unit, because I don't see how the same designer can make two products with the similar circuit sound so different. I would love to tinker inside with those huge coupling caps. The Snapper's input/driver circuit is same as Shrimp, and sounds great.
Good luck!
Rich