Originally posted by arteisfoto Thanks to all for the replies. I guess what is concerning me right now is the money. If I sell all my equipment as is, I would probably get around $8000.00 (based on eBay auctions) and then I will have to put the rest to make it up.. I would really hate that after making this big decision a new replacement camera comes out just around the corner... I don't doubt at all that this camera is great, I have been reading a few reviews and it seems like the type of camera I will enjoy. Even though I am not familiar with Pentax... is Pentax just like Leica? a refine brand of cameras? better than Nikon? How many lenses I would I be able to obtain? that actually work with the camera?
If you constantly shy away from buying for fear of an upgrade coming out, you will never buy anything at all. If you are selling all your gear to finance your purchase then you need to research, research, research. Have you tried the camera out yet? If not, you definitely should to see if it suits you in it's build and handling. I don't believe (unless I've missed it) you've told us what genre of photography you normally shoot. If it's action/sport then the 645D is a poor fit. If it's landscapes that you do, then it is a perfect fit.
You are making a very big step so ask yourself what you want to do with the 645D that you can't do with a FF camera. I too moved from a 5D mk II to a 645D and I bought the 5D mk III as a back up. I use both cameras for mainly landscape photography. If your approach is fairly slow and methodical then the Pentax will suit you well. It will fill up your hard disk very fast though. I put a 8GB card in my 645D the other day and in my mkIII it would give me around 300 shots. In the 645D it gave 86. I always shoot in RAW so my file sizes are generally large. Also have a look at your computer set up and check you have the best processor you can afford and loads of RAM
I would be very reluctant to change systems completely overnight. You'll need a little time for aclimitisation, as there are differences to be discovered. I would hold on to your present gear for as long as possible so you can have time with the new camera and see how it compares. The IQ is outstanding especially with good glass.