I have a 6X7 and I really like it, it takes wonderful photos with as much or as little depth of field as you want, and focus so sharp you could almost cut yourself. There is plenty of resolution for cropping, and it might just be me, but I think the colors look better, it may just be that I shoot crappy 35mm film so don't take my word on the color thing.
You may hear complaints about shake, but I have never even put mine within less than 3 feet of a tripod and I have only had a problem once with 160 film indoors at night without a flash. Generally with a 6X7 if your photos are blurred, you moved it is not the mirror. Don't blame the tool.
Also contrary to what you might hear, it does not weigh a ton, it just starts to feel like that after you carry it around in your hands for a while. This is not a camera you want to just get and go hiking with, you will get used to it, but it may take time, I was out in the woods hiking with mine within a few weeks, your actual mileage may vary. If you are carting that Crown around, the Pentax will be slightly more compact, I don't know about weight difference between the Crown and the Pentax.
If you do get the Pentax I highly recommend the hand grip, the strap lugs, and a good strap for it, you might think you don't need them, but trust me you do.
You may want to keep that Crown Graphic a little longer, or until you can replace it with a 4X5 field camera, you may miss that big negative.