Hi
@markastin im currently using a 640. I can't say I have any especially insightful experiences of it. It works fine, the menus are fairly navigable.
If you are planning on starting with the sensors do be aware that Medtronic are experiencing severe supply issues with the sensors currently which may well delay any start with sensors for new customers.
What I would advise for starting on a pump and getting the knowledge of how to get the best out of your pump, and make the start up process a bit easier, is to get hold of a copy of John Walsh pumping insulin. It like a text book on how to use an insulin pump and well worth having a read of before you start pumping.