Spurgeon at Revzilla's Common Tread has written a lot about the 400. Though he says many positive things, he estimated the service costs for the first 15k to be over $1,500 at the shop. And while he says this includes parts, I don't imagine he's talking about tires, pads, sprockets, chains, batteries n such. I think he's talking about labor costs mainly. Of course if you do the work yourself, you pay only a fraction of that. This said, the number suggests that maintaining the 400 may be just as labor intensive in the end as the 500. And while the 400 doesn't seem to be a tech heavy bike by today's standards, I get nervous at the idea of having to take a bike into a shop for computer "diagnosis" which very well may tell you "Replace this expensive part." I don't have to worry about that with the 500. The 400 has fuel injection--but knock on wood, I have never had a problem with the 500s carbs in 60,000 miles of riding. You'll be able to get the 500 a lot cheaper, and the insurance, at least in my neck of the woods, will be a good bit cheaper too. For all of these reasons, I prefer the 500.