As of now I don't think there is anything special. The Inktomi thing isn't a factor anymore. NSI is getting a little better in their customer service though and they are the registrar most businesses like. I think Bulkregister is alot better but you have to pay a yearly fee to use it which makes it only good if you do alot of domain names. NSI will probably be around after other registrars belly up if it comes to that. Watch your renewal fees. Some registrars hook you with 1$ or $10 but there are almost always catches. If you resell domains make sure your registrar is compatable with NSI. Some can't transfer very well. Also, check the fine print on who actually owns the domain. NSI used to have a clause stating that they owned the name you would register but I am not sure now as I no longer use them. Some registrars actually lease names to you and can take them back at their whim so be careful.
About a month ago I found it totally impossible to make a nameserver change with a domain registered with NS. After several weeks of constant emails, I had the client change registrars - over to the place I use (a Tucows reseller) for $13.50. It was done over Thanksgiving weekend, and we had her up and running in 2 days. But the struggle with NS delayed us enough to miss AV submission in time for the Holidays.