If you're located close to an REI store I'd go with the REI, hands down. They have great service, free tune up after break-in, and their house brand is always good value. Plus you have a year to return it if the fit just isn't working out for you.

Bikesdirect is good value, but if something is wrong the service is via mail.

If you don't live near an REI store then all those bikes are roughly equal value, but still I'd lean towards the REI (you could still return it, but you might have to do it by mail).