From my monitoring the "registrar dialogue" it appears, for that past several years+, that they all equally suck in their own special way.
Re GoDaddy - GD nailed the "successful domain registrar" model a long time ago, which is why they're as big a player as they are. The money was never going to be in providing domain registration. Noooo. They money was always going to be in the (overpriced) value(?) added services: hosting, privacy, blah blah blah. GoDaddy has always pushed a seemingly endless supply of "addition offers you should consider". Bleh. Just renew my damned domains. NOW, thank you.
Other than the "common suck factor" my persistant relationship with Moniker, since Monte's departure, would border on inexplicable. I can't say I've had serious issue with Moniker but I will say that I miss the old days of being able to promptly get someone knowledgable, able and "sounding concerned about me/my business" on the phone. But, as I indicate above, the money/profit isn't in selling domains, customer service, etc. The real money is now in the registrar grabbing any dropping domains . . and parking them . . and putting them up for auction . . or keeping them and parking them once the newest version of traffic testing (redemption cycle) reveals there's money to be had.