Ahh, my first adventure into BL, and what a lovely little journey it was. I was, admittedly a shoujo buff who intially wrote off shounen-ai as 'male-centric shoujo with sex', and I was very, very wrong. Love Stage!! is an enjoyable ride through the romantic struggles of our leads, lovingly ripped straight out of the first arc of the manga, minus the, uh, slightly more naughty parts.
Let's dissect the story, and uh, since I have not read through any other BL, I don't have much of a point of comparison, but it reminds me in a way of 'Tonari no Kaibutsu-kun', at least concerning our main characters dynamic for the first couple episodes.
In summary, 10 years prior to the beginning of the series, the young male Sena Izumi is unwillingly recruited by his celebrity mother Nagisa to fill in for a young girl during a commercial shoot. It is here he meets a young Ichijou Ryouma, who helps him out with the aid of a good luck charm after he screws up a take out of nervousness. It turns out that these screw-ups drew Izumi away from the spotlight and towards the path of the mangaka (which he isn't all that great at). Ryouma, never knowing that Izumi was a male, fell in love with him, and used that love to claw his way to fame and sucess. Having the influence, Ryouma manages to get the whole original cast back of previously mentioned commercial (Izumi included), just to confess his love to the 'girl' he had been dreaming of all this time. Chaos ensues, and eventually Izumi's true gender is revealed because of Izumi's rock star brother, Shougo; cue gay panic on the part of Ryouma. More chaos ensues, lots of elephant euphamisms later, and we have a great little romantic comedy.
In terms of differences between the anime and manga, the anime really just cuts out the more graphic interactions between the characters, and I think it works better that way. The anime also does a few more things with the Lalalulu character which I simply loved, which made her more than just the obsession of our protagonist.
Animation wise, it looks JUST like the manga. Hell, it managed to really bring a lot more life to Izumi, especially in his eyes. Very colorful, not so much realistic, but it doesn't have to be.
I admittedely don't pay much attention to sound, but it never went against the tone or mood, which is all I really care about. My only gripe is Shougo's voice actor: to call him annoying is an understatement. WISH!
I love all the characters dearly, at least the principal four of Izumi, Ryouma, Rei, and Shougo. I kind of wished the parents broke the 'celebrity parent' mold we see even in western works, but they aren't awful. Izumi and Ryouma have some lovely chemistry, and I found the whole gay panic thing too hilarious. I admit that Izumi kind of takes the female-boy trope to new heights, considering he turns THREE OBSTENSIBLY STRAIGHT THUGS TO ATTEMPTED RAPE, but when he's not troping it up and even going at odds with it, that's when I love him the most. Ryouma does have 'perfect boyfriend' syndrome, but the way he relentlessly chases Izumi makes him endearing, at least to me. Rei and Shougo essentially act as Izumi's real parents, and they have that bickering old couple thing about them I find so adorable.
Overall, I loved it. The chemistry works, the plot is gloriously contrived, and it really just forms a stellar viewing experience. The manga does have a ongoing second arc (albeit with the mature content level of the manga, so be warned, kiddies!) that I really enjoyed, so go read that if you liked this anime.
TL;DR This BL was awesome, everything works, highly recommended. WISH!