Enfamil Gentlease Vs. Similac Alimentum

Ok mommas, Xavier has been on Enfamil Gentlease for the last month or so. He has been doing GREAT on it. His pediatrician sent WIC the prescription for the Enfamil, but they won't cover it.(which is bullshit) So, the pediatrician sent a prescription for Similac Alimentum. Any mommas have LO who are on it? I hate to switch his formula once again, but I'm going to give it a try. Anyone know the difference between the two? I've googled it, but all it says is that the proteins are broken down just a tad bit more than the gentlease. He's been doing so great on the Enfamil and I'd hate for the Alimentum to not agree with him. I'm about ready to say the hell with WIC and just buy his formula like I have been! Why won't they cover Enfamil? It looks like they'd cover every type of formula there is. Any info would be greatly appreciated! :)