So far Gandi was posted as reliable company and over last 10 years I had no issues with them. One good feature is that you dont have to be owner to renew domain name registered with them. So in case you temporary lose access to your account you can still pay for domains. They also allow to keep credit balance for auto renew.

I really didnt have much of issues to talk about so no idea how good is their support at solving them, but at least I have peace of mind when it comes to renewal.