We are using it on a rather beefy server with no problems with a Win32 client/server app.
There are additonal things you can do to tune the database.
I've not seen any stability problems. Remember it's been several years since version 8 came out and the current version is 9.1.2.
pgsql-general by date:
Соглашаюсь с условиями обработки персональных данных