The increase in price isn’t huge, but it’s enough for people to notice and have a quite a reaction. The increase is quite different depending on whether you subscribe yearly (a $10 increase), quarterly (a $7 increase) or monthly (a $1 increase).
I think that this increase in price seems to be quite fair. PlayStation haven’t increased the price in PS Plus in years and the quality of games that come with the service have risen in the past few months.
Obviously, with this kind of announcement, most of the reactions so far have been negative.