Had both, only have Rugers now...
The Buckmark is a great gun, but I don't like that the barrel is held in by a screw...a steel screw, into an aluminium frame. I didn't like that you have to remove the rear sight and barrel to properly clean it (well, to ME, properly clean it).
YMMV obviously; if you're one who doesn't scrub their guns detailed clean every time you take it to the range, or is content with a boresnake to clean a barrel, then you won't have an issue. Me...I'm one of those "carbon attracts moisture which attracts rust" people, so I always detail clean everything after a range trip.
Having said that, the Buckmark does have a lot of things going for it. I really liked mine. I just didn't like how it disassembled. Then again I'm one of those guys who has no issues with stripping a Ruger, unlike some folks who find re-assembling it requires some sort of witchcraft...