Overall I thought that the premise of Strike Witches was pretty decent. I found the war against the Neuroi thing to be quite fascinating, and I have always been a fan of alternate history. However, the story seemed to take to much of a light hearted tone in the middle of the series, and then it quickly changes into a deadly serious piece, which didn't seem to fit as well with the rest of the show. Other than that the story was pretty good.
I felt that the art was quite good throughout but there were some things that I didn't find visually appealing. In parts of the show, it seemed that the characters didn't fit in with the backgrounds and scenery. I also felt that some of the backgrounds were not immersive to the characters. One last thing was that I felt that the characters sometimes could convey emotions, but I can excuse that as them being in the military. When you get beyond that though, the art can shine.
By far the best thing in this anime. I found all of the characters to be interesting and unique. They were all lovable in each of their own ways. I personally liked Shirley myself, but this is the kind of show where anyone can have a favorite character.
I felt that Strike Witches was a decent anime and that I would recommend it. However I know that there is a second season, but I'm not really sure how they could continue on with the story, since this series wrapped everything up so nicely.