Glasgow School of Art is not part of the university, but does have very strong links with it. My course is split between the two, but most, including Architecture, are based exclusively at the Art School. You will have nothing to do with the university (aside from drinking at their unions, joining their societies etc.) if you do Architecture - unless you make friends at the uni. That said, the Art School does have its own union, and a good social scene... if a little pretentious.
The entry for Architecture at the GSofA is extremely competitive, and you need a solid portfolio and some knowledge of architecture to get past the interview. It is a good course, however... I don't know about the Strathy course. To be fair Davie, there are only a few unis in the West of Scotland, and of them, Glasgow is miles ahead in terms of recognition.
The accomodation isn't brilliant at the Art School, but not particularly bad, and on a level with some of the stuff the uni have.
Tell the people that are snubbing the GSofA to read up on their facts before they talk ***** about it - My course will see me graduating with a MEng... How exactly would I be getting this if I didn't attend a real uni?