If its casual it may not be an issue, but mainly for the image rentention problems, some plasmas while I cant recall the actual reason/definition for it have input lag, im not quite sure what causes it but some people say they feel “input lag” when gaming on some plasmas, newer ones tend to have a “gaming mode” which supposidly helps with this, as I do not game on my plasma I cant comment on my own experience. I do know a few people who do play say 360 on their plasmas without any issues that they report.
If your not a hardcore screaming in your mic 10 hour a day gamer, its probably would not be an issue.