As a reseller, I prefer not buying names at odd registars, just for the sake of keeping track of them, the logins/passwords, and expire dates. I avoid godaddy if it's near renewal, because they have a rule not allowing transfers out within 60 days of an ownership change. I don't like name where each individual name has a separate management login. If they aren't combined, it's too many to keep track of. I prefer registerfly becaue transferring a domain to a new user is as simple as pushing to their email address. I like selling from enom, because even though a little more work, I can put the name in a retail account and make a buck or two if they leave it there and renew through my reseller account or register new domains. I absolutely hate wildwest domains because you can't push them to another wildwest reseller account or godaddy without a transfer, and each wildwest reseller has different logins/passwords and prices, as well as the godaddy 60 day transfer hold rule.
In buying for resale, It's easier when the names are with enom, registerfly, dotster, or a lesser extent godaddy. Namescout wouldn't be bad if prices weren't $25+, and I avoid NSI like the plague.