Yay, this thread is exactly what I needed. I was looking through Yelp last night and New Day had a lot of good reviews. Glad to see that it's been recommended here as well. I'll consider Delancey and LimoRes also.

I'll be arriving EWR at 11am on Dec 24. I figure I'll be fine taking the AirTrain + NJT option as outlined in the wiki. That's $12.50 to Penn Station, 25-40 minutes travel time, right? Is there a reason I should consider car service instead?

My flight out from JFK is at 9am on Dec 30, though, so I figure I should leave at... 6:30? Would it be easy to get a cab from my hotel (near-ish Grand Central) or would you recommend a car service?

Also, has anyone had any experience with R&G Henry Limo? They offer the Benz Sprinter limo. I'm interested in it for travelling around Manhattan. There's only one review on Yelp for them, which gave them 4 stars but the reviewer didn't even use them..