The LRP v7.1 is almost unbreakable - I've even put bat-plus to esc-minus and bat-minus to esc-plus a couple of times.... That usually burn down the ESC, but not the 7.1.
I find it's easy to program, no need for the manual, after the initial getting used to. Which was quite fast.
I would also suggest getting the SR, it is better suited for stock.
That might be the main difference between the GT7 and the 7.1 - the GT7 can better be adapted to different motors and tracks.
But then again, the used GT7, how old is it? Is it from the first batch, that John Bull mention?