EGNH
Try
www.airlinequality.com.
You will see that Delta has mixed reviews. I've generally found them OK although their JFK terminal is prone to congestion. Helps of you like Pasta & Pizza westbound. They are introducing seatback TV and this includes 757s.
The main reason for going via a hub is to get a cheaper fare (for example LHR - NRT may be cheaper via ZRH). If the fare is the same you might as well travel direct (unless you are an aviation enthusiast and see a change at AMS as a bonus).
Baggage will be automatically transferred at AMS if you are travelling KLM throughout and yes 1 hr 45 is adequate - well in excess of the minimum connection time of 50 minutes in the Official Airline Guide.
Bear in mind that CO flies direct MAN - Newark (OK for Manahattan) and Pakistan Int'l flies to JFK three days a week so you could check prices for those airlines. I've no experience of the latter.
You won't get the ATC though. As Avman says only UA and then, I believe, only domestic sectors. (Someone correct me if I am wrong).
Have a good trip!