I already saw all episodes online years ago and continued through all the manga, but bought this just because it deserved to be bought.
This is the best mecha type anime short series I've seen and the best one out in years – if not ever. Quality and classy production and animation. The machines are hand drawn. Storyline is top of the line for action anime; ‘original’, mature without saturated fanservice and cliche anime techniques. It is an anime though, so they can be found (maybe one true instance, but tasteful).
The only negative about the collection is the last episode, as Roger's review notes. It changes its ending from the true story found in the manga.
This is not a hit and miss. It hits hard in 5/6 episodes. I encourage you to continue the series through the manga by any means possible (e.g. phone, tablet manga reading app).