I'm not necessarily disagreeing with the previous post on the 5000 series tractors, but I'm a big fan of the 4000 series tractors with eHydro. Unless you're haying or planning to do some serious ground engagement work, the 4520 with eHydro transmission is a very versatile and capable machine.
I have been mowing about 8-10 acres with a 6' rotary cutter behind my '09 4720, which has about the same PTO hp as the 2010 4520. The 4520 would easily handle a larger cutter.
It takes me about 1/2 hour or so per acre to mow my hilly terrain with lots of obstacles. I feel very safe mowing near my ponds, and around obstacles with the eHydro. I was not as comfortable with my old manual tractor, which was my main driver for upgrading.
If you plan to do any heavy work with the FEL, I highly recommend liquid ballast (i.e., Rimguard or CaCL) in the rears. This tractor with the 400CX loader will serve you well, in my opinion.