Little more than backyard football with some unique tweaks and rules. I'll watch maybe a game to see some of the new stuff.
I think the only viable alternative for spring football was the USFL and it just couldn't compete with the churn of the NFL, for many reasons. But a bunch of us went down to watch Herschel and the Generals in Birmingham, and it was fun. The league had real athletes who the public knew about and played some good ball.
Unfortunately, some owners were stupid about football and finances. Being wealthy doesn't automatically make you smart. Like other leagues - see the aborted Alliance of American Football, along with other minor league teams everywhere - they needed a salary cap, a commissioner with balls to keep the egotistical owners in line, and none of that happened.
The USFL was fun, though. I think this new McMahon league will be gone in 2-3 seasons, at most.