I applied for Quebec residence in 2006 and finished the process (and moved permanently to Montreal) in 2008. The process is straightforward. It's more expensive since you have to pay the Quebec fees and the federal fees and it doesn't necessarily go faster (in my case, Quebec wanted to interview me which made the Quebec process take longer than the federal process.)
The one thing I'd advise anyone considering Quebec is to really make sure that they both understand and are OK with Quebec's culture, Quebec's laws (esp. as they pertain to language issues and the education of children), the job market, etc. This is good advice if you were immigrating anywhere, but it's especially important when considering Quebec. For myself, I've decided that Quebec is not really working for me and I plan on moving to Toronto in the next year. That's not to say that Quebec wouldn't work for someone else.
You could probably make a much longer list, but here are the things that stand out for me:
Pluses:
+ Inexpensive Higher Education
+ More reasonably-priced housing
+ More comprehensive (though flawed) social programs (inexpensive daycare, more comprehensive health insurance)
Minuses:
+ Language laws/non-stop politics around language issues/heavy pressure to toe the line on "living in French"
+ Tepid job market/lower salaries
+ Significantly higher taxes
Good luck, whatever you decide.
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