I went through the same analysis myself. It's very difficult to choose two years of expensive education with little income over three to three and a half (at least, realistically, knowing myself) with a full time job. In the end I chose to try for full time first, and if that fails, I'll try for part time.
I spoke to some part time friends and I've had more than one tell me that they wish they had applied full time, in fact, now that I think about it, I know of only one person who recommended I go part time. Everyone else, alumni, and current students in the part time programs recommended full time.
These are basically the reasons they quoted:
1. Yes, you can complete in 3 years or maybe even 2.5, but its going to be non-stop and very hard to do. Realism indicates 3 to 3.5 is more likely for demanding programs.
2. While part time is great, balancing a full time job with the demands of what is basically a near full time mba program anyway, is hard. Doing so for 2 years without a break is really pretty impossible, hence why it tends to take longer than that.
3. If you think you might switch careers, full time is the only option. The recruiting and opportunities to network in your planned career will far exceed those in the part time program.
4. You compete with full time people in classes who have a lot more time to actually study.
5. Some universities explicitly DENY you access to recruiting unless you get a letter from employer saying it's OK.
6. Don't forget about the clubs that you can be a part of.
7. The people you meet in your classes will be there one day, they wont the next. That is, every quarter you end up meeting different people because everyone is on different schedules, people take different quarters off, etc - so it becomes very hard to establish deep relationships when you only know people for 2 or 3 months at a time.
These elements combined with my personal situation made full time seem more logical. I admittely don't know if I'm going to switch industries - probably not - but I'm definetly switching job function as much as I can, so I'm sort-of a career switcher in that sense. (But I'm not going from say consulting to IB at least).