This is the last good one.
I don't know who else agrees, but I think that not only is this by far the most underrated part, but it's the last one I really liked. It was relatively well-written, the characters were fun and the protagonist, while first a bit of a dick, became awesome in my book (with tremendous acting by Winstead) and it even has great deaths. I think part 4 took away all the charm and stripped it away by using the 3D gimmick and making it too over-the-top, not the entertaining kind of over-the-top. It also had terrible character, I think there was only one I liked. Part 5 is a huge improvement, but it's full of flaws too, in that it for example is too similar to the first one by trying so hard to be like it. It also has some of the negative elements of part 4.
The first three is a perfect trilogy. The fifth one is worth seeing, but not that memorable. The fourth is garbage. Complete, utter garbage.