Collin Swrote a review of Praxis Works Conversion Bottom Bracket for PF30 - MTB on October 24, 2014
Familiarity: I've put it through the wringer
I put just under 2000 miles on this bottom bracket on a Single Speed Mountain bike in mixed conditioned, including a good amount of muddy days. There is no creaking, and the bearings still spin well. I've noticed single speeding kills bottom brackets pretty quick but this one so far has fared well. Only heads up is to make sure you have 2 bottom bracket tools on hand, as well as make sure you get the right bottom bracket for your application. Shimano uses a 24 mm spindle on both sides, however, Sram/GXP is slightly smaller on the non drive side. The one sold here is for Shimano cranks. If you want to run Sram, either call up Competitive Cyclist and have them get you the Sram version or call up Praxis and buy it directly. The other option is to run a small shim. Not the best solution, but they are available (BEER components sells one).
Although not advertised directly, the bearings are replaceable with a professional press. The downside is. Praxis will void your warranty if you do this. If your okay with nixing your warranty, Praxis has the actual part number for the bearings in their FAQs for the bottom bracket.