I have about 600 with GoDaddy and a great account rep, T.D., who deals with any query, usually within minutes.
I have them all on auto-renew just in case I miss one but when I get the first renewal notice I'll send my rep an e-mail asking her to bulk renew anything due in the next 3 months at my discounted rate, 1-2$ under the standard rate. If renewals get a bit close my rep will e-mail me as a reminder. Great service!
Been with them about 7 years and never had a problem.