"David - I do a lot of integration to and from Netsuite using Boomi. Netsuite has a comprehensive API, and the Boomi Netsuite connector provides access to most everything in Netsuite, including custom objects and fields. Boomi is a great choice for Netsuite integration.
Here is a recent Blog post about Netsuite and Boomi: http://www.kitepipe.com/blog/netsuite-integration-with-boomi-perfect-together
And a whitepaper about handshaking basics for Netsuite and Boomi, to get you started: http://www.kitepipe.com/resources
For conversion, smaller simpler conversions to Netsuite can be done with the Netsuite batch loader, which takes CSV files. I've done CRM conversions from Salesforce using just Excel. Netsuite, however, needs its own internal keys for more complex conversions, and Boomi is a good tool, as the lookups to related objects can be automated. I wouldn't get Boomi just for a conversion, but if you are buying as an ongoing integration platform, it can be really useful in conversion, esp. with use of Netsuite sandbox, pilot and production cycles, etc.
Boomi has a powerful set of SQL connectors and tools, as well - I'm currently doing a conversion from Oracle ERP, including customers, orders, etc, into a specialized Printing industry ERP system, Radius, which is SQL on both ends.
The Boomi services team is great - I work closely with Ed, Jim, Adam and the services team at Boomi. Its a small team of experts, and the SWAT team for Boomi implementation issues. They are great for their quickstart offering, and the training is highly recommended. For a longer term project, you might be better served with a specialist services firm like mine - http://www.kitepipe.com
Boomi is a highly productive tool, and most projects don't need a Boomi FTE resource. All the other moving parts of the project (data quality, specifications, workflows, netsuite customizations) are the schedule drivers, so we typically do fractional staffing, or Fixed Fee, to support a conversion or integration effort.
Good Luck! Netsuite and Boomi are a great combination. Feel free to contact me if you have questions! firstname.lastname@example.org"