I was given a small book on revival by NG... I remember that it was encouraging and seemed for the most part pretty straight forward (biblically speaking) but I do remember a few moments that gave me pause, overall it was a good read. It's called continuous revival I think-
Having read this, I was interested in reading more of his work and that's when I discovered several things that I couldn't square with my understanding of the scriptures based on the light I have... which doesn't make him wrong per se, tho I chose not to read by him any further.
I've noticed that this has happened with several writers/preachers including David Wilkerson Watchman Nee, etc... but in the case of DW, I still read/listen to him. Nee however, like Grubb, left a mark that requires me to be very cautious, and I'm less likely to read by them at this point. (Tho I've read lots of Nee books and enjoyed them)
For me, it seems allot of times people get distracted from Jesus and make it be "about us",... and wind up with a man centered gospel.
Sorry for not being more helpful-