nice apples to oranges math
OP--you're missing the fact that difficulty is about to spike like hell. Welcome to the arms race again.
Yes, it's better to buy but in some places *cough US cough* it's MUCH easier to buy mining equip than it is the coins.
In the case of GPU's you also have a hedge against a massive price drop.
I'm with you. I just got into this so I'm sure I don't know how bad the spike will be, but I would expect it to be much more difficult quickly as people see the potential. Worth the gamble in my opinion