I'm not confident in google scholar because sometimes it considers some publications of other authors, similar in the name with you, belong to you. Then in this case, the index of google is wrong. This is happened with me. I found under my google scholar a lot of publications which are not of me. Then i got a high wrong index. But for honesty, i deleted them.
A ranking based on the H index seems to be a tendency in many countries (it seems that IEEE use it also). However the issue is to get the right number. In this context, RG seems to vey interesting as it allows calculating the H index excluding auto-citation.
It seems that Google Scholar starts to be adopted by universities as an evaluation tool (just to have an idea). Thomson reuters has something equivalent but it is payment-based (access to citations and so on).
PS. In France Google Scholar-based H index is used and an additional information for researcher evaluation for promotion purposes.