I think how much use of it you get will depend broadly on two points.
Most importantly, as it seems you're aware, the QC series annontations generally don't spend much time explaining the plans each side aim to follow. What this means is that I feel you MUST have a decent amount fo experience within the opening complexes that are examined (not necessarily the precise variations).If you've never played the Nc3 french before, maybe you want to clock some hours getting feel for it before resorting to a highly theoretical work.
The second important point, which is related to the first, is how you generally like to learn from your opening books. Books from quality chess , I find are very useful if you go to them after your games to find where you, or your opponent deviated, and slowly accumulating knowledge of the theory. However, if you like to read books cover to cover in a short amount of time to get an overall feel for the positions you play, its probably best to go with a book that has more explaination, and is in full game format (Most QC books are tree format).
I've read a lot of good things about GM Negi's 1.e4 repertoire books, but as it's from Quality Chess' Grandmaster Repertoire series, I'm a bit hesitant on buying it. I loved Marin's 1...e5 series from QC, but I know that QC aims the GM series at higher rated players, and as a 1600 player OTB, I'm not sure if I would get much out of it. So for those who own it, is it worth a buy? (and please don't go off topic and say that I shouldnt use opening books at my level. I review most of my games and do tactics daily).