Mache - as Marc noted, no one can tell you which is the "best", as best is a relative word...what works for one person may not work for someone else.
I am not here to cheerlead for any town, or for myself - just to give you some information.
I will say that each of the 3 Caldwells has a certain flair and distinct flavor....your price range will also factor in, as, in general, the home prices in N. Caldwell can go into a higher price point range than Caldwell and West Caldwell.
N. Caldwell makes use of West Essex Regional Middle and High Schools - shared by the towns of Essex Fells, Fairfield and Roseland. Caldwell and W. Caldwell make use of the same middle and high schools(James Caldwell High and Grover Celveland Middle).
Both school systems are higly ranked.
If you check my website, I have provided links for more specific school information on all the towns in NJ, and a variety of other useful sites that will give you more town information, as well.
Best wishes with your move......potentially, Welcome to NJ !
Prudential NJ Properties