A Marlin 60 was my first rifle, way back when. My father bought it for me at K-Mart (pre-Rosie, of course!) and together we slapped on a cheapie little scope in tip-off mounts. Dad and I shot the heck out of that little gun, always buying ammo by the brick! I later graduated to a decent 1-inch Burris, and the little Marlin kept plugging away. I lost count long ago of how many squirrels it has accounted for.
Years later, I bought a 10/22, since I had heard so many raves about it. It was less accurate than the Marlin, had a rather chubby stock and an atrocious trigger by comparison. I eventually traded the 10/22 toward one or another handgun and kept the Marlin.
In contrast to Dave's experience, my Model 60 has been shockingly reliable. At one point, I had fired over 2,000 rounds from it between cleanings -- without a single malfunction! In fact, I can only recall it malfunctioning (aside from the very occasional and expected rimfire misfires) perhaps four times in many thousands of rounds.
As one of the other posts said, unless you're wedded to the idea of customizing the Ruger, the Marlin may be a better choice -- heretical as that may sound. Personally, if and when I feel the need for another semiauto .22, it will definitely be a Marlin.
Mike