I suppouse that you live in spain? I prefer 6th gen cause its easier to get parts, and if you get the one with air bag you can have ABS too, but it depends on you. I don´t know about 5th gen a lot, i have the 6th one so i can´t tell you which you shuld pick.
Pick the one you prefer, both of them are reliable, at least my 1.8 7a-fe is XD