Gotta be the worst part of the entire Monogatari series so far, but that was to be expected since it's a miniseries of short 12-minute episodes and all but two of them are completely irrelevant to the main story. More character interactions with good jokes and thought-provoking puzzles are always good, but some of them have very underwhelming endings. The final two episodes, though? They are very important to the main story and feel almost out-of-place, though I guess technically they are also thought-provoking puzzles as well.
This miniseries, since it was released online, has a noticeably lower budget; its OPs reuse songs from previous story arcs and slightly-remixed animation, and the soundtrack seems to include no new tracks. However, the animation and direction are still up to SHAFT's high standards (well high for the BD release) and won't disappoint.
Obviously, it's a must-watch if you are going through the various Monogatari series and miniseries and movies, but go in expecting some pleasant filler, because that's what you're going to get.
