I've been using Gandi for 11 years. They've generally been great. Initially I was drawn to them because they were one of the first registrars to make it clear you owned the domain name and they were an agent.
I've kept with them largely because of the generally convenient and low-upsell nature of the website on top of this.
One caveat for U.S. customers: on the very rare (once or twice a decade) occasions when I've had to contact customer service, the time separation and some rough English skills have led to a slightly bumpy communication experience while resolving issues, but even with those obstacles, they're better at it than GoDaddy (and their English is a heck of a lot better than my French :).
~$15usd/yr rather than $7ish a year isn't a big deal for domains I care about.