I agree with your wife...and the Harman Dealer's advice. We had the Accentra insert and LOVED the look of it. That said, it simply was not built for really cold weather. We became frustrated by how often we had to monitor the pellets in the hopper (small hopper, so it would be very close to empty when waking up in the morning), and how frequently we had to shut the stove down to empty the very small ash pan. That was enough for me to not even consider another insert when we moved into our new house. Even though I still prefer the looks of the Accentra over any free standing stove, the heat output and conveniences of the P series was FAR more important to me. Not to mention, if you get the nickel trim kit and a decorative tile, you can make the P series look quite nice. The other major difference I noticed is that the Accentra absolutely had to be cleaned once a week, and it was not negotiable. I noticed that we would start losing heat/efficiency about 5 days after we cleaned it. With our P68, it only gets cleaned once per month, and I've noticed no heat loss, at all. This thing is a fire breathing dragon, whether clean or not! I also agree with your dealer that the P series is definitely easier to clean than the Accentra insert was. Good luck with your decision.
Another confirmation for the P68 ! Incidentally, the wife doesn't care for the nickle trim but likes the slate insert or one of them anyway. Actually so do I. Still looking but it most likely will be either a P61a or P68 for it's added insurance regarding heat capability. I don't want something that looks pretty on the hearth but barely heats the living room !