Eh I thought first one was decent, with second and third ones being the best with 4th and 5th ones also just being okay to decent.
I'd go about it this way.
Dirty Harry 6
Magnum Force 7
The Enforcer 7
Sudden Impact 6
The Dead Pool 5.9
A lot of these movies bring up a threat and they just become irrelevant. At least in this one he gets body gaurds after threatening the mob boss he testifies againts. In the Enforcer, that story line just dies. It serves as a set up and then becomes irrelevant.
Compared to Beverly Hills Cop and Leathal Weapon, this is at the bottom of the 3 series. I love it when the movies are darker and serious, but these fail at. I mean beverly and leathal aren't serious enough, but those buddy cop flicks, so i have different set of expectations) Plus the cinematography is pretty average in these as well compared to other movies of its time.
That's just how I feel about this series of movies.

I like all of them.

Magnum Force is great

But the first movie doesn't have "Go ahead, make my day", Harry's other famous line, despite what many people think.

Its because The first film is a stone cold classic in a different league to the rest

I see.

I think each of them has value.

This message has been deleted.

this one is my favorite

I liked Dirty Harry, Magnum Force, The Enforcer and The Dead Pool. For some reason I don't remember much about Sudden Impact.
I think Dirty Harry and Magnum Force together are the best.