Once you go MAC, you'll never go back
I've had my IMAC since last May. Prior to that, I considered myself a PCperson, but never again. You'll love your new mac
Regarding buying RAM from Crucial, I inquired at the MAC store and they said if I put another product in my MAC, it would cancel out my Apple Care. Because of that, I purchased the RAM through MAC, which was expensive, but worth it.