Good amp match for vinatge Vandersteen 2C's?

I find them soft as well, Solid State seems like the easy answer. You are lucky in a way as most less expensive amps will work well I would think. There are a bunch of D class amps with oodles of power available fairly cheap. Bryston makes some Class D and class A/B. Bel Canto, Wyred4Sound, Sanders, Red wine, etc.

McCormack!

I'm using a Krell KST 100 with my Vandersteen 2's. It doesn't offer the smoothest upper mid/treble but it helps to offset the Vandersteens. I also have a Rotel RB 1080 that I like and that works well. They talk about Vandersteens being so good you can drive them with amps costing more than $5K but in the real world people who buy Vandersteens used for $600 aren't buying such expensive amps. I've heard a McCormack DNA 0.5 on Vandersteen 2Ci's that sound nice too.