From time to time I have encountered Power Tab (mostly at Ultimate Guitar Tabs) version of tunes. I have the paid version of TablEdit on my iMac so when I open the Power Tab it automatically converts into TablEdit. So I have no idea what the "native" Power Tab looks like or how it works.
You can get the free TablEdit reader -- but you are limited in what you can do with it beyond reading it on screen.
Power Tab is a free (freeware) PC program.
Is there anything that Power tab can do that you can't accomplish on TablEdit?