I'd like to know the major maintenance problem you may have to content with by having an Plasma compared to a LCD TV

Also when you are moving this TV downstairs without an outside entrance what major problems may you encounter.

The main issues with plasma are burn in problems. They can be eliminated and combated by turning down the brightness for the first 100 hours or so until the TV is broken in. Also, if you are playing video games, make sure you turn the TV off if pausing for awhile.

As for moving. Patience is your best friend. A 63" screen is cumbersome. You don't want to be in a hurry or try and move one on your own. In fact, move the screen IN THE BOX, where it has additional padding to protect it. Also place blankets/towels inside every nook and cranny. And perhaps even use a dolly to move it if working by yourself.

Lastly, adjust the color/sharnpess contrast and brightness (as previously mentioned) to meet the particular lighting conditions in your home. Most people don't realize that the default settings on a TV are designed to make them look better on the showroom floor and when they get them home, they are disappointed with how they look. Adjusting settings to fit your particular room lighting will help dramatically.