I used to be OK with Namecheap but the Web 2 redesign makes doing most things a pain.
1. Namecheap has a really low API limit which caused me problems when using the DNS challenge to renew Let's Encrypt certificates.
2. Their API has to have clients whitelisted by IP, which is a pain when renewing a LE cert from a dynamic home IP.
3. Agreed, their redesign is awful.
I used Gandi recently to get around these restrictions and:
1. Their web UI is truly awful and confusing
2. They don't have the same IP or rate limiting restrictions on the API
3. Their versioning of zones is a bit confusing
4. Their propagation seems to take an age longer than Namecheap. When the latter worked each LE challenge took a couple of minutes, with Gandi it's more like 20 minutes each.