I can thoroguhly recommend Gliding to PPL's - I did some Gliding with the ATC and Channel G.C prior to commencing my PPL and then did some more Gliding just before completing my PPL (I managed to get my A cert' on weeks course at the Cornish G.C at Perrenporth - a magic week in the sun with a marvellous instructor Ken Wooley and a co-participant who was a 737 Captain.)
I definately feel that gliding improves your flying & makes you more aware of the science of flying in general.
Apart from all that I found that Gliding folk are very friendly
and above all else Gliding IS fun !