Unless you’re very close to WestChester I wouldn’t recommend it. As someone said earlier it’s very small, limited (and expensive) food and drinks landside and even more limited in the large room that is the departures lounge!
Biggest drawback though is its small size an the fact that in the case of any throttling or closing down of NY airspace HPN invariable loses out – as I found out (again!) last July – and priority is given to EWR JFK and LGA! That and limited airlines with direct flights (via Jet Blue) and I’d choose LGA or JFK any day of the week unless I was actually in WestChester or Somers etc.