I love Patsy's, and have many fond memories of the place, but not my favorite pie.
My current fave is Johnny's in Mount Vernon.... but you have to eat it there (the pie does not travel well - it gets cold way too quick, and loses its flavor on re-heating), and they don't do slices (probably because of the previous statement), so unless you're going in a group or feel like being a complete pig...
My Patsy's recommendation is second hand--both my sister and my father told me---I haven't tried it yet. I no longer live in New York, but when I did I loved Ray Bari's Pizza on the upper east side, a place called John's near Buhre Avenue in the Bronx, and Louie's Seafood Restaurant on Treemont Avenue in The Bronx---Louie's also makes the best Calamari Marinara I've ever had. Good Italian food is the thing I miss most about New York. Even more than going to the Stadium
I live sorta near Buhre ave. Best pizza up near there is Louie & Ernie's on Crosby Ave. Crosby pizza works well in a pinch, but its not my fave. There's also a cheap (but really good) pie to be had at Pinnochio's Pizza (on Buhre). Large pies for a decent price - and taste pretty dang good... in fact, its where we order from most often.