I have 3 stars in everything. The 150cc felt really cheap to me, like getting tanked in the last turn of the last lap of the last race of a cup. It just made me come back for more until I got that 3 star monkey off my back.
However, I think multiplayer is more fun than ever before (especially with friends) and I really love the time trials as it's more centered around finding the right lines as opposed to snaking of old.
To qualify that, I was the biggest snaking bastard in MK64, MKDD, and MKDS, but truth be told I'm happier with bikes finding the right line and wheeling my way through a straight.
The one that gave me the most problems by far was mirror cup. I'm HORRIBLE after I know a track inside and out, trying to do it flipped. Those always took me forever, but it was mostly my failing rather than items.
3rd Party Wall of Shame
http://www.nintendoworldreport.com/forums/index.php?topic=30478.msg581036#msg581036
