You might be lucky and get a good tyre, but you might be unlucky and get a bad one. At least when you stick with what others use and rave about, you are almost guaranteed to be happy, if a little out of pocket.
I have certainly had good "cheap" tyres in the past, but I have equally had crap "cheap" tyres too.
Personally, I buy branded tyres, and have gone on other peoples recommendations in the past, but now prefer to judge for myself and I try various brands.
For what its worth I have had a few seats of Goodyear Eagle F1 GSD3's and the latter ones were not as good as the first ones. The Pirelli P-Zero Rossos that come on the Cupra are good tyres but they were ruled out for lack of side wall protection. I recently added Bridgestone Potenza RE-040's to the front of my Cupra and so far they seem ok - a little hard perhaps which is meaning increased wheelspin, but hopefully they will outlast the 10,000 miles the OEM tyres managed.