so is press the attack basically dead on melee champs

No, it's actually the best choice a LOT of the time but the critical thinking and game knowledge to recognize where and when doesn't usually exist until mid grandmaster and up :)

I use pretty much only PTA on jungle fighters like Trundle, Shyvana, and Warwick. It is good on anyone who has an auto reset.

Personally, it's one of my favorites on Skarner...but nobody really plays Skarner. It's arguably really strong on Udyr too. These sort of sustained damage, "you cant outrun me!" types love it.