I am at USM and have had a very mixed experience. There are instructors who care about students' progress and do a great job. There are instructors who do little. Overall, though, I'm happy with my choice: You can't beat the price. It made it feasible for me to earn a second bachelor's degree.
Price and NCLEX pass rates were big factors for me. According to the state BON, the pass rates for first-time test takers in 2006 were USM, 88.28%; St. Joseph's, 78.8%; and UNE, 73%. Best in the state: UMaine Fort Kent at 100% (and only eight people taking the test).
If you're interested, all of the pass rates
are listed here.