Robert,

Part of the equation is also weight. If you can afford the extra weight go with the eXtreme 5s1p 5000's, in your first year of Advanced you'll have enough to learn that you'll need as much air time as you can get. Even with the TP 5300's I couldn't come close to two Advanced patterns (at least with last year's pattern). Nine minutes seems pretty short when you've got a lot to learn.

If you can't afford the weight then I'd recommend going with the Prolite TP 5300 5s4p cells. These are lighter than the 5000 eXtreme packs and will give you more flight time than the eXtreme 4200's.

Your first year flying electric you're going to be getting accustomed to how much throttle is required and 4200 mah doesn’t give you much goof-up room before you begin damaging the cells.

Keith B