We've used Incapsula (cheap and works, but awful support and service) and Distil (expensive and works, great support but steep pricing). Both worked, both work

We've used Incapsula (cheap and works, but awful support and service) and Distil (expensive and works, great support but steep pricing). Both worked, both worked well with http downloads and selenium (and common techniques). Neither worked against someone dedicated enough - but there are the usual tricks for bypassing them (which we used, to test our own stuff). We also developed something in-house, but that never helps.