I use each for different purposes, I wouldn't be able to fairly compare them. I am in a long-distance relationship, and we do use skype everyday to talk. We use the mobile apps to call during the day on our phones and chat at night with video. For that purpose, Skype outshines any similar service.
I voted Google Talk because, aside from my LDR, Talk offers a great alternative to using my phones services (I dont use GTalk with my boy, the international rates are still more than Skype). I can text from my computer, make and take calls, and stay relatively anonymous with my second phone number. I use it in several situations: as my screener number (when a person or business needs my number that I'm apprehensive to provide for, since GTalk lets me block numbers and Sprint doesn't), as a separate 'business' number for any temp business idea I have running at the moment and other odds and ends that I dont want to give out my cell for.