Be sure to double-check that the specific TK fare classes you're booking earn UA mileage (assuming that is important to you). When TK rolled out the Comfort product fare structure there were some glitches re: automatic UA mileage posting.
Also, enjoy the TK Comfort product while it lasts! My understanding from sbm12 (this is not firsthand knowledge) is that they're not expanding deployment of the product and don't plan to keep it.