Wavac vs. Air Tight /300B's

Open to advice...I'm currently running a Joule pre into an Air Tight ATM300B (with WE300Bs, Mullard/Chelmer 12AU7s, Natl Union 5U4 rectifier & RCA red-letter 12BH7s) and am seriously mulling over switching to a Wavac MB-300B. I am also looking to move from the Joule to a Shindo, so that would be a consideration. The Air Tight is a fine amp with great dynamics and extension, but I would be looking for greater tonal color saturation and harmonic complexity with the Wavac. Any opinions/impressions? Thanks for the input.