For me, no question I'd take the frontier. But i like things like out of the box reliability, accuracy, good looks, ability to use lots of types of ammo... etc. If you dont care so much about those things and just want a gun to makeover into something else like a tactical rimfire, or you like to spend extra money on aftermarket parts tinkering with your gun to make it "better", then go for the ruger.
For $400 you can have a decent ruger, but you have to put in the work of upgrading the snot out of it, changing extractors, barrels etc...
Just read some of the current threads on this page about 10/22's. It's pretty common. Many people love them though... after they have invested several hundred extra dollars into them.