Thanks everyone for all of your feedback. We are actually going with Silver Star Limos (based in Yonkers). They are the only place that has the car we want - we needed a limo that comfortably holds 12, so we chose the Porsche Cayenne - it's like a Porsche SUV! I'm psyched :)
Since it's considered an SUV it's more expensive than reg cars - $900 + tip for 3 hours. But since we're only getting one car we were able to justify the cost. Thanks!