A quick search shows 2 AA flights to LGA, 4 DL flights to both LGA & JFK and 3 UA to EWR. Currently, JFK & LGA are operated by Republic, EWR showing 1 mainline UA and 2 on Go Jet. Routes, frequency, and operators change over time but if you were to work for Republic, you'd likely have no issue commuting. If you were not with republic, it would likely still be pretty easy to commute, just be aware that priority is usually given to whoever is operating the flight. So, lets say you get hired by Endeavor (Delta), any republic employee would bump you on their metal and regional planes only have 1 flightdeck jumpseat.
I am not a commuter, nor do I live in the BUF area, but my quick search of options would be enough for me to consider it very doable. However, I do not know how many NYC pilots might be living in BUF. YMMV. Hope this helps a bit.