Have you seen the 2015 model of these?
http://gripitfixings.co.uk/new-gripit-2015/
They look to have addressed some of the installation issues of the original version.
I'm interested in them as there is a fairly heavy cabinet that could do with fixing on a partition wall which is basically two sheets of plasterboard with a cavity of several inches and no nearby studs etc. Not used the spring toggles / umbrella fixings for anything 'meaty' before so have steered clear of the task up until now but perhaps these new type are worth a look - although TTC's horror story of the previous type is a concern re quality even if the design has improved...