Has anyone moved to SuiteTax here? I need some tips and heads-up about migrating to SuiteTax. Any tips, documents and suggestions are most welcome. Thanks in advance.

It really depends on the nexuses you have, if you have multi-book and the complexity of your taxation. General advice would be to test everything thoroughly before moving to production, especially tax reports. You can compare your legacy tax reports with the SuiteTax ones to make sure they are the same.

You need to be really on top of it, it is sadly a big deal - but it is very hard to give specific pointers without knowing what you have (use cases, countries, nexuses etc. as AK also stated.)

there are a lot of changes with SuiteTax. So be prepared to redo many things if you have some integrations with external systems, custom reports with tax fields or any other customization. Also keep in mind that some generic tax related bundles are incompatible. Basically everything is stated in Netsuite documentation.