I've got no experience with the Browning Buckmark, but a lot of folks here seem to think highly of them. However, I own and would recommend the Ruger Mk4 Target with the following caveats:

Pros: moderately priced; accurate; easy to take down & clean; many after-market options for grips, sights & magazines.

Cons: requires Volquartsen (or TandemKross) trigger upgrade for match accuracy; requires replacement of firing pin (Mk2, VQ or TK recommended) to eliminate probable firing pin breakage; some people have reported loosening of the barrel-to-frame pivot requiring replacement of the original flexible grommet/buffer.

I would recommend also the Ruger Mk2's but they're a pita (...in my opinion) for reassembly after cleaning. Most owners, however, eventually get over this annoyance and regard them as superior in many ways to the Mk4's and Mk3's.

-S2