Look at absorption rates.
For instance, right now Randolph has 8 months worth of single family listings on the market (i.e it is going to take 8 months for those places to sell). Compare this to a market we all know is hot right now despite the general iffy market - the South End in Boston - which has only 4 months of condo inventory on the market. Now look at Dorchester, a market that is tanking right now, they have 11 months of single family inventory on the market and 13 months of condo inventory. The conclusion you draw by doing this is essentially supply and demand. These numbers tell us Randolph is doing ok, but not great. The best way to determine where you should put your money right now is to take the 4 neighborhoods you are considering and see what their comparative absorption rates are and then go from there. See where the demand is.
If you need me to walk you through it I can no problem.