The Manfrotto 488 RC2 is the mopst popular ballhead recommendation here and its value is reinforced when you realise that the next ballhead worth buying, the 468 Hydrostatic range IMO, costs 3-4 times the price. Then tthe next step up to the big boy RRS and Markins gear is even more.
I didn't want to pay out for a head I will not use that much, just mainly for landscapes with ND Grads during my next Africa trip. But I did want a super steady platform for the camera with long exposures and maybe panoramics and then a simple, flexible QR system.
I decided to get the 488 without a QR
and then add a Manfrotto 577
eBay clone QR and plate. Screws together great, super steady, no movement, strong, nice QR, safety catch, plate runs full length of the body and you can slide the plate along the QR base as needed. Very nice indeed 
Cost around £75 delivered for the pair. Maybe you can replace your existing QR - I've never tried to unscrew it on previous models. Sweet ...





