Thats easy.
Which gen angel are you talking about?
The older generation angels (LCD, Ir3) are laid out exactly like the ego (LPR up front, valve in the middle then ram comes out the back). I could do one of those in under 40 minutes comfortably, and I could strip and rebuild an ego in a similar amount of time (probably slightly longer).
The newer generation angels are a little more user servicable, I would say 25 minutes tops. But I do admit I get alot of practice teching guns.