Hey, atleast you're getting a copy, you should just be happy about that.
Having G4U or not really depends on how bad you want it. Vol.1 is one thing since you get a bunch of other things in the box set so the extra money you spend on it is actually seems worth it. I dont know about the other Blu-ray x G4U packs though. With the current exchange rate you'd end up spending about $115 on each volume. So far most of the outfits featured in G4U is available in the regular game, so really the only difference is that you can get the girls to pose in a unique setting. There are other things beside the G4U that come along with the set though, like the special CD and the "GraDol" gravure booklet. Think of "GraDol" as a gravure magazine that'd exist in the iM@S universe. Different girls are featured in each volume. Vol.1's GraDol featured Haruka and Iori...*pouts because it wasnt Yayoi, Hibiki, nor Makoto*
There is however the "Communication" Mode, BGM list and the "Pandora's Box" in G4U. The "Communication" mode is just a really short conversation with the featured idol of that G4U volume, nothing too special. As far as BGMs go in vol. 1 there's a unique track called "Haruka RedMIX", its basically one track composed by combing existing songs into one remixed track. I think "RedMIX" combined "I Want", "Do-Dai", "Go My Way", "Over Master", "Tonari ni...", and "Kirame Kirari". There are a couple of other tracks featuring DLC songs like Hibiki's "LOBM", etc. Dont know if they'll do a similar thing in each volume, like add a "Mami YellowMIX" in vol.2.
The "Pandora's Box"? You'll have to refer to my post in the iM@S game thread in the forum since there arent any spoiler tags in here.
I have no plans on buying any of the other ones except for whatever volume that Yayoi will be the cover girl for and whatever volume comes with the GraDol that features Yayoi...though hopefully it'll be the same volume...but I wouldnt put it past Namco Bandai to seperate them. Well, maybe I will buy them all...if I ever win the lottery.