Since the patent expired on the AXIS Lock, a few competitors have emerged.
First and foremost, Doug Ritter's RSK, and not just because of the knife.
If you want choices, just search for "crossbar lock" on your favorite engine or website. This is where things get complicated, if country of origin is a factor in your choice.
Hogue seems to be the consensus choice when people want a non-Benchmade crossbar lock that's made in the States. Prices are about the same though.
If you're willing to consider other manufacturers, Kizer does a good job with the Drop Bear, and Kershaw has gotten into the game. Vosteed and CJRB make some, so does Knafs, a newly-formed company started by some cutlery enthusiasts.