Conwy or Cardiff

Where are you starting from, and what time of year?

I feel like the answer also depends a bit on time of year and how long you have, as well as what you want to see.

Is this just for an overnight stop or are you wanting to see something of the place? Cardiff is a large bustling city. Conwy is a small medieval town. They are completely different.

If it's just a "hit and run" I would say Cardiff because there a lot to do right there in the city. To me, the things to see and do in North Wales are more spread out.

Thank you everyone.

We have visited both places and enjoyed them both.
Conwy is in North Wales and Cardiff in South Wales.

Conwy is a small town with the large castle. Cardiff is a large city, but has Cardiff Castle and The Museum of Welsh Life that are great to visit. Also, there are more castles a short distance from downtown Cardiff.
We also loved Tenby and St. David (at the tip of SW Wales).

They are quite different experiences. North vs South, city vs small town.

I've been to Conwy. It has a castle and nearby beaches. It has a weekend getaway kind of vibe. Nice if you are nearby, but not a destination.

I've never been to Cardiff. I just know it as a large Industrial Revolution city.

PS: There is a "Wales" section of this forum. You might find better responses there.