Grabbed vol.1s of all three.
Interesting how Splash Red was leading in sales.
Impressions:
Red - I don't really like the artstyle, but yeah, Ai's energetic and that's all that matters.
Seems to have the least story progression, although we see Miki in the last page, highlighting the turning point in Ai's scenario.
Blue - Smells of yuri, and actually looks like a manga that popped up from Comic Yurihime.
Story doesn't have much progression, and it's pretty much Eri figuring out her place in the outside world, much like the first section of Eri's scenario.
Green - By far the best imo, though this might be because KuroseP actually loves Im@s, a lot. He manages to squeeze in idols that don't appear in Ryo's scenario in random, appropriate panels, awesome.
As far as story goes, it seems to be progressing the fastest, with the Ryo-Makoto training arc/part of DS being covered fully. We're also left with a cliffhanger with Yumeko, which I like.
But really, the cover should have been Ryo and Makoto, seeing how Ritsuko doesn't appear much.