Keun I'll try to answer your questions as best I can, though I don't have the answers to every single one of them.
I've never bought any Anime from either this site nor any others. How are the subbings? I like it when the subbings are colored differently for each character in case two or more characters speak at the same time
Each company that releases DVDs has their own way of subbing things. That said, of the subs that I've watched, they tend not to change colors based on the character speaking. Whether that holds true for all subs I can't say.
And do they have subbing for Opening and Ending songs? In another word, karaoke. I love singing along so if that's missing, that's a no no.
I would say nearly all, if not all of the anime I have seen do have the opening/ending sequences translated on screen (usually included on the DVDs as an extra is the "clean" opening and closing where this is removed.
Is Gakuen Alice going to be dubbed? I heard rumors about it. Although I do NOT like dub at all. If they do dub, the DVD set also better have sub version with japanese audio with it.
Gakuen Alice is not going to be dubbed. Every anime DVD set that is dubbed that I have seen always includes both the English dub as well as the original japanese audio with subtitles.
I have also never experienced any problems with subtitle timing either. Not to say it doesn't happen, but I haven't seen a release where it was a problem.