gosh, that is such a toss up. as a contractor, i've done both. sometimes i sense from a client that they don't want a hard sell and i let them be, to make up their own mind. other times i have the mental bandwidth and time to follow up and see where they stand. it could be that A has been in business for awhile and understands that half of quotes don't lead to business so is sanguine about it, or is busy enough that 'selling' isn't a priority. But B's follow through could be a sign of attention to detail. Or desperation. The fact that their pricing is so close is an excellent indication that they both understand the industry standards and can make accurate estimates for time and materials.

You didn't actually say what way your gut was leaning. Based on what you've told us, I'd say B, due to the combination of good references and the follow through. But if your intuition is telling you something different, have you nailed down what that is and why? And there is absolutely nothing stopping you from hiring the other person for handy man work later on, even if you don't hire them for the painting. [good] contractors learn not to develop fragile egos about that sort of thing.