Heyoo!
 Anyone else having this issue? Im in Canada on a PS3, and whenever I connect to the Music Store I get about 30 seconds of good browsing, and then I get a "Unable to Connect to the Music Store server at this time". Googling I see posts about this going as far back as 2010. Dafuq? Anyone got any ideas on it? 
 
I'm fully connected tot he PSN and can do internet quick play, so it cant be an internet connection issue..
 
Also, if I purchase the packs through PSN rather than the Music Store will I be able to use them?

You can purchase tracks from all 3 rock band collections in the PSN store. I do it all the time since the in-game store doesn't let you use the shopping cart feature. The in-game store uses the PSN store for transactions anyway, the only thing you miss without it is audio previews of RB1/RB3 songs.