Hey Jeff,
I asked this same question a while back and got a mixed response. In my experience any "good deals" on the MLS are quickly picked up by savvy/ready to buy/established investors. My feelings on this topic are that investors who are early in their career should try to focus on deals that are not on the MLS. I may be totally wrong, but it seems that the profit margins are larger in non MLS deals. In short, when something is on the MLS the investor is generally going to pay what the market dictates(this may be wrong so please don't take my opinion as fact).
I prefer to deal in markets that I have an advantage in as a buyer. I am particularly interested in tax deed sales because it restricts the market to cash only buyers(in my county). I feel like using conventional financing takes up too much of our profit margins, so my strategy is to avoid it.
Realtors know more about this business than we do, but they are not going to work for free. When searching for deals that are not on the MLS I have found that most realtors are not interested or don't know enough about non MLS deals to be helpful to early stage investors.
Hopefully someone who is in the know can chime in and better answer your questions. These are just my limited experiences in the business and if nothing else it'll bump your thread!!
Good Luck!!!