There is a good place - gochat.in, the site is very simple but people are fine:)
The people ARE indeed nice, and it's probably the best way to test your language skills as a foreigner, but the vast majority of users is aged 14-18.
I used this site to test my language and speak about daily stuff, as well as to test my understanding. It works nice, but after 2-3 visits it's unlikely that you wish to go on.
Besides, truth to be told, Polish teenagers make more spelling mistakes than a foreigner who's studied the language for 6mo+.
I don't dissuade anyone to go online there, tho'. :-)