We did our implementation directly with NetSuite Professional Services, thinking that would be better somehow. But they sub-contracted much of the development work anyway, and they made a mess of many things that we are still cleaning up 7 years later. I'd vote for a partner over NS any day. And you definitely want someone with experience to warn you what NOT to do. There are certain pitfalls with any system, and only someone with a lot of experience with that particular system is going to know what to watch out for. NetSuite is no exception.

This is probably the most common feedback, I really wish we would have researched beforehand