The Manabi Straight Special is a pure filler episode, wedged into the continuity somewhere between ep.6 and ep.7. I had a tiny hope that it would be some kind of a follow-up episode or a reunion, but alas, it did not happen. In the same time, over-sexualization a-la Kamichu ep.6 did not happen either. We just get a bunch of pretty pictures (there's a ton of pan-over-still, too).

Since there's no any great story such as in the main show, the Special underscores animation issues. The biggest one for me is that character designs in Manabi are not made to scale up. They are vectored in a computer, and the same model is used for all zoom levels. Therefore, close-ups tend to suffer. To illustrate, small and medium zoom shots vary from pretty decent to outright gorgeous:

Chest-up shots are so-so. Below, Mei is probably one of the better ones, because she has eyebrows. The gradient hair, pioneered by Manabi is in full force. Also, there's a little overpaint on her right jaw (I think a dilligent animator tried to compensate):

However, this Momo really received a bad treatment. She came out completely flat-faced:

Notably, the main show is generally better with working around the design. Here's an example of Mikan from ep.5. The incomplete confining line on her jaw was a very nice touch, although some kind of two-tone shade would be welcome too. The cheek color serves to break the large flat area.

And of course it gets pretty good above the nose level... Which is where real close-ups tend to concentrate.

I don't regret getting the DVD, but on the other hand it could be much more if only the creators wanted. I do not recommend getting it unless you're already a die-hard fan. The main show is highly recommended instead.