Good lord, I don't know how I didn't see this post.
The Smash offers the obvious benefits of more line level inputs and outputs, wall power, and all regulated power supplies. I find the Smash to be quite a bit less microphonic than the Quickie, and the greater available high voltage helps the overall performance of the circuit considerably. It also has way more space for different components if you want to mess with different coupling capacitors.
The Quickie does favor the tube rollers, however, as the 4P1L was made with very good consistency.
-PB