I have played on a LOT of different sites, over 40 up to now, and I have found that players play differently on different sites. You might get a site like 888
which is a fish pond as against PS where I find a higher standard of player, thats only what I feel, others will feel different.
Dont worry about having " never been beaten by a site" if you are losing get out.
I used to play on 2 sites mainly, I play 6max PLO, Inter Poker and PS and these days it is 95% Inter cos I get Rakeback there and at small stakes it makes a hell of a difference, PS VIP scheme might be great for high stakes grinders, but not for micro stakes players like me.
Really tho you answered your own question with your last sentence
"The title of this thread is because if I cant see where Im going wrong at PS, then there's no point me playing there (and losing), when I can play at every other site and win. right"