I have never had any problems with Newegg and have been buying from them for years. I have read some horror stories on here though that make me wonder. They ship to me while I am deployed over seas with no issues and when I am in the US they ship just fine as well.
I have never bought anything from NCIX so couldn't speak to them. But everyone's buying experience is different, and newegg offers a lot of great products so if its customer service you are after, then try newegg out and see if its any different maybe your experience will be better with them than NCIX maybe it will be worse, you won't know until you try though.