I'm having a tough time deciding between the two. Have heard/watched/read good and bad about both. jon4lakers on YouTube (whom I generally trust) says the Sensation is fantastic. I, unlike many others, am primarily interested in call quality, and particularly speakerphone quality.
Coming from the BlackBerry world (well, I also have a Nexus S and iPhone 4), I don't think anything can compare to the BB's speakerphones, but if someone could comment on these two models, I'd be very grateful.