I was hired last week. Top to bottom, it looks like a great company. I've been friends for years with a Mesaba captain, and he's always spoken highly of the company. At my interview, everyone else was coming from another regional, I was the only flight instructor.
Chances of getting the Saab are great...I'd say 90%. The only CRJs are going to laterals currently at Mesaba or UND grads who took the CRJ transition course. Senior base is MSP. Expected upgrades are hard to tell, but I'd say 3 years. We were told we need 3000 hours to upgrade, but after 1000 hours each hour counts double, so it's really only 2000 hours. If you max out at 100 hours per month, that's 20 months to become *eligible* to upgrade.
Mesaba had about 600 pilots before the growth. They're hiring about 600 more, and are 1/3rd of the way through that hiring.