I used G+ at WDW a few weeks ago. I cannot say anything about DLR G+. It sounds a lot like like the old DLR MaxPass which I did use and liked.
On the WDW
MDE app Disney has a lot of kinks in their system that is making a lot of folks really angry. If you read the WDW forum there is a lot of negative press for G+ and WDW right now.
At WDW I used their FP+ a number of times. If G+ worked properly I think it is a better option than FP+ for WDW. G+ worked great for us at MK. It was frustrating for DHS because they are letting too many people into the park and there is not enough to do to spread people out.