The Petzl Spirit Express is its main competitor and has a similar solid gate keylock design. The Spirit is a little lighter, little easier to pull rope through, and the Spirit has grooves in the gate that make it a little easier to do reachy clips. We prefer the Spirit, but the Black Diamond Positron is much less expensive ($16.95 vs $22 for the Spirit). Since the Positron also is a great biner, we wouldn't hesitate to recommend it if you are on a budget. Or, for $15 you can also get the high-scoring Wild Country Nitro Quickdraw which is much lighter than the Black Diamond Positron but comes with a wiregate (no keylock). If you just want the most carabiner for your money, it's hard to go wrong with the Mad Rock UltraLight Quickdraw for $15.
Positron Quickdraws 381014 / 381016 / 381081 / 381082, 381077 / 381078 / 381044 / 381058 were recalled by Black Diamond in February of 2016. If you think you might own any recalled quickdraws, check out this safety recall notice to read what your next move should be.