I think the last 2(?) seasons lost the essence of what made Black Mirror great but the older ones are excellent. Older episodes often felt directly applicable to the evils of technology we use today but these newer ones seem to be more generic Sci-Fi, season 6 didn't feel like Black Mirror at all to me.
I haven't actually watched the last two seasons yet but the first ones are amongst the best stuff I've ever watched on a screen. So thank you for the heads up.