I used a cheap 5-man rotation in a no-DH league for Barnstormers with an 80M cap and it went pretty well:
https://365.strat-o-matic.com/team/163404386-76 with a loss in the finals.
The 5-man rotation strategy hasn't worked any better or worse for me than a 4-man. I think the pricing difference between * and non-* works out pretty evenly on a per inning basis (that is, it is about a 20% difference in price for the same quality player, but you need 20% more of them, so that makes sense).
I have a couple other active teams with 5-man rotations, but the leagues are often themed leagues, so those results are maybe not representative of a "normal" league setup.