The general consensus at the club is that the U23s league is a bit **** and the lads gain far more experience playing men's football where there's actually a competitive element, the U23s calendar often has gaps too which means some of them go weeks without a game. In terms of development, it's far better to be playing and learning than it is to be having a relative kickabout against Crewe reserves.
I always thought it would be a good idea to enter a reserve team into the Humber Premier League (and just not have them get promoted), but I don't think it's allowed, which is odd because at the same level there are other non-league reserve teams across the country.
EDIT: Just looked at the rules, reserve teams can go no higher than Step 6 (which is the Northern Counties East League Division One - the same one that Beverley Town play in now/Ferriby just got promoted out of), but there doesn't appear to be a rule that states a club from the football league can't have a reserve team in non-league.