First, Toshiba isn't very reliable. One of the more faulty ones I think.

For the others, if one of them is a Sony plasma then it has to be seriously old. Sony quit making plasma TVs like 6 years ago or more. So there is absolutely no way anybody you know bought a Sony Plasma tv not even a year ago. If they did it had to be some second-hand old tv that somebody else had already used. Come to think of it, Toshiba quit making plasma TVs too. Oh, and Bravia was never a plasma line.

The other S brand? Sanyo? Another not so great brand. Screen problems were very common with some Sanyo models. Sharp? Doesn't make plasma.

Plain and simple, these days, Plasma delivers a better picture over LCD. LCD is closing ground but still plasma is outpeforming LCD consistently in the picture department (black levels, contrast, color accuracy, response time/refresh rate, etc). Even viewing angle, LCD hasn't fully caught up yet. Plasma is even cheaper when getting into big screens (which is all plasma does). And technically, to an extent, plasmas perform better over time, not even hitting their peak performance until you're well past the break-in phase.

As for burn-in. That's just being careless. Plasmas made these days have so many built-in features (and the technology has been improved) that burn-in only occurs from careless use. And if you can make it past like the first 200-250 hours of viewing without causing any burn-in, then the coast is clear. When my TV was new several years ago, I'd never dream of leaving a still image on there long. If I paused a movie, I'd turn the screen protector on. Gaming was never even a problem, I'd just make sure to turn the screen protector/clean wipe on for a few seconds every hour or so (and this was only with games that had a hud or something that was ALWAYS on the screen). Now that I have so many hours on my TV though and it's been broken in, I've sat and left a game paused on screen for like an hour and not even the faintest sign of burn-in.