Definitely mid-power for me, since all I do is gliders, lots and lots of them.
LPR is great, but you cant get too large a glider with C motors, no matter how light you try to end up.
Ive done like 12 or 14 HPR gliders, mostly back in the 92-99 range, and while these are a sight to behold going up (and down, no matter how so) just were too few chances to afford and fly them, not to mention loss of the local TRA prefecture back then didnt help.
That leaves midpower, and with better material selection/use, Ive managed to actually end up flying the same sized gliders as Ive used to on HPR, with only F/G motors. Sure, they dont have that I284 or J90 exhaust/flame, but they sure make up for it in glide!
There are so many things you can do with 'just' an F or G motor, you just have to design right and build light, and thats right.