"Bridge drug" is kinda true, but let me offer this slightly more positive spin! I went to MF, went "whoa! I want more," and then went on to LF, just like everybody usually does. :rolleyes:
But... then I turned back quite enthusiastically to MF and became a lot more interested in it. One big reason being that there are some really superb 120/220 films now. Films like superpan, atp, etc. Not to mention the price of top-notch gear, which is absurd low at this point.
I'm just saying, let's not let acute formatitis prevent someone from discovering how fantastic a 645 or 67 neg or slide can be.
For architecture, I'd say the rb is also not the best choice, unless you are willing to do scanning and digital perspective correction and such (which is a very viable route, actually; I am just saying). Even a $200 old crown graphic kicks the butt of pretty much any slr for architecture, IMHO.