I just went through the same buying decision dilemma - P 40+ vs. p 45+, and which lenses for mostly landscape work. I went with the
P 40+ for many of the same reasons mentioned above. I can live without the longer exposure time, but the larger sensor crop still makes
me question my decision. I do like the fact that it's the newer technology, and the sensor + has actually been more useful than I thought it
would be. But also, as posted above, I've started thinking I should have really left some funds available for a technical camera and some lenses
for the back, but I guess that will have to wait. Good luck with your decision!