I am writing this review from the perspective of having beaten the SNES version (not counting Lavos shortcut Game+s) at least fifteen times. To get the easy parts out of the way:
(1) People who have never played Crono Trigger and own a DS and don't hate RPGs- must-buy. Thousands of different reviews anywhere on the internet can explain why. The story is not terribly innovative, but is executed very well. And considering the graphics (which still largely hold up for me as great stylized art), music (spectacular), depth, replayability, etc.- its one of the greatest games of the 90s, and imho of all time as well.
(2) Crono Trigger Fanatics like Me- if you are a fanatic, you already own this. And if you don't, you'd buy it even if it added one new item or character. But be warned: they have changed some iconic lines of dialogue which may cause nerdrage. They even changed my sig line to something far less cool.