I detest the infant years but I had babies with issues. Everything after that has been largely terrific. You give something up but you gain something with every year. Older teens now and they are simply terrific. That said, I always hated saying goodbye to the previous iteration of my children. The shiny 4 year old remains only in photos and video.

2-3 is PEAK cuteness, adorable. Even their mispronunciations are so darn cute.
4-6, they are still so impressionable and innocent. Amazing to see them soak in everything they see and hear and learn.

My kids are 17 and 19. I've enjoyed every year with them so far.

0-1 (you’re just so tired) and 2.5-4 (they’re just so unreasonable) are the worst years; everything else is debatable/kid dependent.

My older DD is 8 and I'm really liking this age. We're able to have real conversations now, we watch TV shows, play sports in the yard and bake stuff together, etc... but she's also old enough to go off and play on her own (or with a friend) with pretty minimal supervision. Still young enough to be goofy and gullible and think we're the coolest people in the world. No tween/teen attitude/angst stuff yet!

My younger DD is 3 and I'm ready for this stage to be over, LOL.