From what I hear it takes about 6-8 hours to get to 85. Really glad I didn't waste my money.
I had decided if I was going to play I was going to take paid time off from work and skip classes for the week to race for server first 85, regardless of whether or not there was an achievement this time around. Luckily term papers and exams for grad school messed that up. I'd be really PO'd right now if I had wasted all that on a 8 hour level grind.