Fixing plasmas is a doddle. Take the back off, find the board which is giving problems (usually Y-SUS, Z-SUS or power board, remove the cable connectors and board mounting screws, replce with spare. Job done. Simples!
I've never had a plasma with pixel losses, only ever power board problems. Have bought and sold a great deal of them too.
When you buy a new plasma, just make sure the brightness/contrast etc are all at a sensible level instead of at full setting for the first few hundred hours viewing. A lot of these plasmas also have a timer in the service menu to see how many hours they have been in use. A word of warning, never buy an ex-display plasma from a shop. They have all the settings on very high and will have been in use for many hours before you get it. Not good.
Panasonic we have:-
Panasonic TH-50PZ800B Large Plasma Television Screen - Digital Direct