Domain Registration

I’m interested to hear any comments regarding HC-compatible domain registration companies. Which one(s) provide the best experience for HC users?
 
I saw an old post saying that HC supported domain transfers only for Enom and Realtime Register. Is that still true? Are there any other implementation differences between registrars, that a reseller or webadmin would notice?
 
I would prefer to avoid any company that pushes unwanted services or sends excessive email to customers.
 
Thanks!