The VT60 is decent for gaming performance. It differs for every person how susceptible they are towards the lag. Frankly geordiemp is a bit exaggerating imo, it is possible that he does notice the difference, but for most people such gaming performance is great.
I game on the ST60, which has way more display lag and I play games fine on it. That said, I have played no twitch shooters on it. It is also definitely possible that I play better with less lag, and I really wished Panasonic would have done something it, but I have no regrets buying it.
About image retention, I haven't had a single case of image retention on my TV yet. And I have played games with static HUDs for maybe four hours at the time. Also some amount of TV channels, but not a whole lot. Now, I have only used my display for probably less than 300 hours now, and I do take care that I turn the display off when I pause the game for too long, so I do have a bit of caution.
Image retention does definitely still exist though, and there have been many reports of it, you may get lucky or unlucky. Many people use it and burn-in interchangeably, but burn-in is permanent and image retention is temporarily. It would take a lot of abuse and bad luck to cause burn-in, and that is very unlikely to happen, image retention is possible but as I said, I haven't found any sign of it yet, might be luck of the draw though.