Is it advisable to get units with store warranty vs the brand warranty? The price diff is significant.

Sabi ng saleslasy, if magkaproblem during warranty period yung unit, you can't bring it to the official service centers, sa kanila daw mag papaayos. Kung gusto ko daw sa service center e me bayad na.

Are these the "no warranty" gray units being sold online, for which they provided/invented store warranty?