Crash 2 is the best crash game period, it's a vast improvement over Crash 1 and Crash 3 failed to live up to the same potential that Crash 2 had.
I mean in Crash 2 the was a least one new type of level introduced in every warp room;
-Warp room 1, all the level are new and gives you a taste of what to come.
-Warp room 2, introduces the sewer and Polar bear level.
-Warp Room 3, introduces the ruins level and changes the bounder level for a giant Polar Bear.
-Warp Room 4, introduces the digging level as well as the bees.
-Warp Room 5, all the levels are brand new.
Now if we compare that to Crash 3 they heavily recycle the level theme for all the warp room and every warp room has at least one vehicle levels, whereas in Crash 2 they were less common and spread out, plus Crash 2 had little secrets to find in levels but Crash 3 only had 2 and one of them was stupidly well hidden.
All Crash 3 has going for it is the power ups, time relics and little detail like collectible making a dynamic sound when collected and the box counter telling the players how many boxes are in a level.