Narita airport to Hyatt Regency

There will be four of us, is it cheaper to get a taxi from Narita airport to Hyatt Regency Tokyo? Or is it cheaper to go by train? Is that express train? We will be going around Tokyo by subway, it is worth buying a JR pass?

A taxi costs about 20,000 yen or 5,000 yen per person.

The direct hourly limousine bus from the airport to the hotel entrance costs 3,000 yen per person:
http://www.limousinebus.co.jp/en/timetable/narita/shinjuku_h...

Other access methods to Shinjuku Station (the cheapest costs 1190 yen per person) are explained here:
http://www.japan-guide.com/e/e2027.html?aFROM=2027_3011

From Shinjuku Station, the hotel can be reached in a 10 minute walk:
http://tokyo.regency.hyatt.com/hyatt/hotels/services/maps/in...

If you stay only in Tokyo, then it is not worth buying a Japan Rail Pass.