I usually only give blowjobs to completion to dudes I know pretty well. And in those cases, I always swallow their cum, even though I don't necessarily love the taste of cum per se. There is something about having a buddy's hard cock in my mouth as he goes over the edge, moaning softly and squirming, that is so great. And as he cums and starts to squirt into me, I love slowing down his thrusting and gently massaging his spurting dick with my lips and tongue, feeling him empty himself in my mouth. Because I am a guy, I know EXACTLY how great that feeling is on the other side, and I like being able to give it to a guy I care about, letting him lose himself as he erupts in my mouth.
And when he is finished, I slowly pull back, let his glistening cock fall out of my mouth -- and then it's down the hatch with his sperm. Swallowing completes the act, and I would never spit it out.