Chrono Trigger is a great port, though I miss Frog's Shakespearian dialect. And the resolution and sound quality isn't as good as the original, but that's just the fault of the DS hardware.
As for Super Mario 64 DS... Ugh. I tried so hard to like that game. I love the upgraded visuals and all the extra content, but I hated how they removed some of the original features (seriously, no metal Mario???). Also the DS hardware nerfed the game severely. In addition to the typical lower resolution and sound quality, the 8 way digital controls just don't work for this game (and don't tell me I can use the touch screen for analog input, it feels unnatural as hell), and the addition of the run button makes the run, jump, and attack combos near impossible.