A relatively recurrent topic. So, wiki page … and so it can get updated as/when relevant.

Wikipedia:Domain name registrar

Will likely well fill out and organize more later, but for starters, some background "discussions"(posts):

Various pro/con recommendations, including fair bit of supporting reasons
some comparing hassles vs. not of, e.g. toggling whois privacy, IPv6 glue records, Gandi.net/NameCheap.com/Joker.com
some pros/cons of "just a registrar" vs. provider of additional services
Gandi SAS (Gandi.net) acquired by Total Webhosting Solutions B.V. (TWS)