What the "good" airlines are is a moving target and will change depending on whats important to you. If you want a good working environment with decent pay and bennies, places like ExpressJet, Skywest and Horizon are probably at the top of most people's list. However, if you want a quick upgrade and dont care if you take it in the shorts for a few years go to Colgan or Mesa. A lot also depends on if you plan to commute or not (see my previous statement about commuting). The fastest way to improve your life at a regional is to live in your base. So to answer your question about the "good" airlines, you need to look at their information and decide which one has the best combination of pay/benefits, location, upgrade time, etc that meets your personal goals and needs. Just remember that the airlines with long upgrades are usually like that because people like working there and are less inclined to jump ship at the first chance. The airlines with the short upgrades usually pay less and have less than good working environments so people cant wait to get out.

Training at most airlines lasts about 8 weeks give or take. That is another thing to look at when you are thinking about going to an airline. Do they pay you while in training? Do they cover your hotel, transportation, etc? Some places like Mesa pay you your full gurantee while in training but they also make you pay for your own hotel (2 months at $60/night will run you about $3660) plus food plus you are responsible for your own transportation to the training center. Other places like ExpressJet pay for all of your hotels and transportation to the training center and then pay you an additional amount called per diem.