Okay, I admit it. I haven't had a chance to try Bobsled yet. It's not my fault, though.* The T-Mobile app couldn't call out to landlines.
Well, now it can. The Bobsled app for both Android and iOS can call to landline/cell in addition to Facebook friends. Unfortunately, you still need a Facebook account. That is, unfortunate for all Facebook haters (see Android market reviews).
T-Mobile also has a Bobsled messaging app; why they would make this separate is beyond me. According to TechWorld, the messaging app is out for Android but won't be available for iOS until later this year. What's nice is that you get to keep your phone number, so friends can recognize you. Many other VoIP apps require a new or alternate number for VoIP calls.
Senior Vice President of marketing at T-Mobile, Brad Duea, thinks getting into VoIP is a good idea. "It might cannibalise some revenue, but we think it's a much greater opportunity. We don't have a fixed-line business to protect. So we're saying, 'cut the cord, here's how we can empower you,'" he said. No fixed-line business? T-Mobile isn't soley a cell service provider? I guess I'll believe it since they're sticking by Bobsled.
*All right, fine, it's my fault. I have unlimited phone and data. That's why I haven't tried it yet.