Below is the message I received from the IT guy at the client referred to above. Pay particular attention to the comment about the governor that Netsuite puts in place to throttle data extraction. I hope this helps.
Hi Shawn,
The tool I had used was originally under the RSSBus brand but is now called CData Netsuite Data Sync. Overall the software did a great job but do plan accordingly on timing, it takes a long time to sync everything to a local database which I believe is a NetSuite limitation of 1,000 rows at a time (or something similar). Thankfully, since I had found a handful of bugs during the trial, they extended my usage 2 additional months.
Here's the link to the software detail: http://www.cdata.com/sync/netsuite/