Having delved into both worlds I am reluctant to say "yes glider jocks make better PPLs"
I agree that there is more energy management and co-ordination (particularly with the feet) in flying gliders but surely there are more aspects of flying which make a powered flyer.
Cross country work, RT coms., radio nav and instrument work spring to mind. How many glider pilots are able to fly into Class D behind British Midlands or whoever?
Horses for courses I suppose.