First time I rode TTD was in 2004, we went during the summertime for about a week to Cedar Point, and I remember at this time TTD was having many issues, rollbacks, constantly closed for a good chunk of the time we were there, but we stayed in one of the hotels right on the island, so we woke (8am) to catch the early opening for season pass holders and folks staying within the cedar point property (one hour before general park opening) we ran and finally got on it! I loved it first time I experienced anything like it. I love them both, honestly 420 vs 456 isn't that much of a difference its still high as heck, and the 120/128... Both still get you to that speed in 3 in a half seconds. I like the theming and lap bar restraints on TTD better then KDK