Have both. Ive spent a lot more time with the Envy than the wa33EE.
I...honestly think I prefer the Envy somewhat (there's something amazing about the texturing that 300B brings especially to bass notes). I have not upgraded tubes on either. That said, I really like the wa33 and it really brings the most of out of headphones like the 1266 & solitaire p. Tungsten/Susvara on the other hand I think are significantly better off the Envy.
Have also tried both with the wa33 preamping the envy. (Holo May -> WA33 -> Envy)
Using both in conjunction with one another was not a huge improvement, but it did feel like you got micro dynamics/detail of the wa33 and the macro dynamics/texture of the envy. It definitely sounded good, but is a far cry from a good value for a fleshed out system.
Honestly, I'd have to give it another shot with more headphones to give you a better impression.
Feel free though to ask if you have more questions.
At this point, I like having both systems to have different gear to mix and match with.