if you were disappointed in the 45-200, you'll be disappointed in the 40-150 as well. They were never meant to compete with the prime lenses in your kit and they have small-ish apertures, but for what they are, I think they are amazing.
I agree that it's not worth it to upgrade from one bottom of the barrel telephoto lens to another bottom of the barrel telephoto lens, even though the Olympus seems to edge out the Panasonic, performance-wise.
No. Stores are currently clearancing any obsolete stock that they have, so that for Black Friday, they will have all the newest, up to date inventory to put on their shelves. On Black Friday, any sales you find will likely be for the newer R version. If you can find the non-R version on sale, while it's still in stock, jump on it if you like the price. At $200-$220, it's still a solid lens. At $300, it's a little disappointing.
It takes some pretty nice pictures. It is far from a perfect lens, in PP I have to apply a lot of Noise Reduction (slow aperture), and boost contrast, saturation, sharpness and clarity. But the end result is often very pleasing.
Remember, it weighs 190 grams. It is extremely compact and light for a telephoto, and it focuses quickly and quietly(I'm mainly comparing it to the 4/3 Oly 70-300).
Image quality takes a hit past 100mm, but it is very good up until that point at 5.6. I see this lens as a complement to, not a replacement for, the 100-300mm Panasonic, and a stop-gap until we get some fast medium teles for m4/3.