We've just posted our thoughts on the IQ260 vs P45+ for long exposures
As always, we tried to make our test real-world and as hard as possible to really push image quality (differences in cameras rarely show up in low contrast controlled lighting tests).
Also, like all tests it is imperfect (for example one of the critical P45+ images is a bit soft, so it's great for comparing color and dynamic range but not great for comparing detail; fortunately we have other files where the 45+ is super sharp for that kind of comparison).
We have IQ260 units in our demo inventory, and units are beginning to ship this week to customers. If this test doesn't cover what you would want to see compared we are happy to arrange for you to do your own testing.
For those that have had the chance to use both the IQ260 and P45+ for long exposures your thoughts from your own testing are very welcome.