That's a great question.
For 2014, the V8 vs V6 question always means 5-speed vs 8-speed. The 845RE 8-speed is more advanced than the W5A580 5-speed in many ways, but in terms of maintenance and durability, I don't think you can go wrong with either one. A quick Google search will tell you everything you want to know on that score.
All other things being equal, I would say that a Hemi Charger with 16% more accumulated mileage than a V6 at the same price is a better value, and will retain that greater value at resale time.
But in terms of which one to buy, there are a few things you didn't mention. Fuel cost, for starters. Nobody buys a Charger for the fuel economy, but you did say that you're a student, and this is your first car. The difference in MPG between an 8-speed V6 and a 5-speed V8 is substantial. If you're in, say, Italy or Norway and paying $6-7 per gallon, that's going to really add up. In the Middle East, not so much. Also, you might want to see if insuring the R/T would be more expensive where you are.
There are a few things that are harder to quantify. The exhaust note of the Hemi, for one.
If gas and insurance cost isn't a major factor, I'd go with the R/T. I don't think I've seen anyone with a Hemi, either online or in person, complaining about their decision and wishing they'd bought the V6.
Good luck!