URF is like DoTA...
In that when it's fun, it's REALLY fun. Constantly being in bird form, basically permament CC lockdown for some champs, constant skillshot wars, it can be great.
But when you're losing, it feels terrible. You tp somewhere, immediately run into a Zed or something, and then promptly get destroyed, to wait for another half minute before you do it all again. And if you manage to win against that Zed, he can just dash away.
I get why people like it, and it's great fun, but if this was permament no one would ever play it.