I'd say building gives more satisfaction, plus ends up to be cheaper because you aren't going through manufacturers that will charge for making and buying them.
I'd never buy a computer from PC company, not in that sense... I would buy parts though, hehe
Trust me, learning is the best part about building a PC. The first time I got one, I watched it being built, and that taught me to the point where I built my next one!
So good luck to you on whatever your desicion