My wife and I asked the same question to this forum when we were starting our home search. An agent on the board reached out to us and he, gave an answer quite similar to Agentarmen. I would add that both real estate agents are excellent local real estate agents and if you were to decide upon using a buyer's broker, then either one of them would be a good choice.
We decided in the end against using a buyer's agent. Our "resistance" to it was that we did not feel that the fee of $4,000 to $8,000 (I think a 2% fee is about standard), as well as us having to sign a contract stipulating that we could only use one agent to look for a place, was worth it. One real estate agent we met was so keen on getting us to sign them as our buyer's agent that we were turned off by it. I hope it doesn't become the expected norm here and add yet another required middle man. Rather it just remain a tool for someone who really needs it. If you have the time to know the neighborhood, research comparables, goto open houses and give yourself an ideas of renovation costs, then you are already 90% there. Pick the brains of everyone you know who has bought a house (supply wine!) and that will help too. Even if you do take on a buyer's broker, you should do those things anyways.
Jackson Heights does have some pocket listings, in that these listings are not available to realtors at large and cannot be found on the MLS. With the internet gaining ground, I'm not sure how much longer that will go on, as seller allowing such a pocket listing will be hurting themselves in the end, though that is just a relatively uninformed guess.
We found our JH co-op without a broker at all and we are very pleased with the outcome.