Ocarina of Time 3D is a perfect remake. Everything that was good about the original is still here, even lots of fun glitches have been left untouched, but changes were made where necessary.

The new graphics are gorgeous. Better textures, brighter colors, new character models and more expansive landscapes make the remake look like the concept art for the original.
The soundtrack is still beautiful and the dungeons are some of the best the Legend of Zelda has to offer. Because of the pacing of the dungeons, side quests and story, I never got bored while playing.
And the quality of life improvements turned the infamous water temple into my favourite dungeon of the game!

Despite all the positives, Ocarina of Time has noticeably aged. Because I'm used to modern camera controls, it took me a while to get used to the fact that you can't rotate the camera, but are only able to center it behind Link. After a few hours, I had no problem with controlling the camera in this way, but the game would still massively benefit from a second analogue stick.
Z-targeting enemies might have been revolutionary back when the original came out and works well enough, but there were plenty of times where I couldn't get the game to target a specific enemy or the perspective would be annoying to work with because an enemy kept circling me.
Aspects of the controls just feel clunky once you've played a modern 3D Zelda game, but these inconveniences were minor enough not to affect my overall enjoyment.
Many of the bosses felt underwhelming, had only one or two unengaging attacks and dragged on for longer than they should have.
Also, getting the golden scale from the Fishing Pond was hell in the remake.

Ocarina of Time 3D is, in my opinion, the best version of the game so far.