I flew a Westwind I for a charter outfit for close to 2 years. It was very solid airplane to fly and also my first jet. We did our initial training at simuflite DFW, it was somewhere along the lines of 2.5 weeks long (~10 days ground and the rest in the simulator). It was my first type and I completed the course at 800 hours straight out of a CFI job. If you are willing to study and ask questions you will not have a problem. There is not any EFIS to mess with, just on old cruddy FMS which I didnt even use. I think alot of Westwinds have been equipped with a Garmin 530/430 combo, the ones that I flew were. I believe the Simuflite sim has been moved to SimCom in Orlando, I have never been there so I am not sure about their training.
As far as the maintenance, boss man always mentioned how much brakes and other parts ended up costing. I think there are only a few authorized parts manufacturers on some of the major parts (like brakes) and they are able to charge an arm and a leg. We had the -3D engines and they were kept on MSP. You can probably find performance data on any number of websites, it has good range and great external baggage compartments with lots of room. There are also some pretty unique nicknames for the airplane...good luck!