Overall, Homura Tamura is an enjoyable comedy 4-koma spin-off of the Madoka Magica series. It obviously spoils some big plot points of the original story, so I recommend you read or watch that one first! Homura Tamura is far from being a masterpiece, but I think it is worth reading if you are a big fan of the franchise.
The story is pretty simple, and I think the manga benefits from that fact: Homura not only travels back in time, but also ends up in weird parallel dimensions with strange quirks. There are one or two times where the story seems to become a bit more
serious, but don't expect anything important or touching happening in regards to the story. It simply serves to facilitate the comedy.
The art looks pretty good in some panels, but for the majority of the time we only get to see the characters in their "chibi" form. These drawings range from still kind of adorable, to sometimes just a bit too lazy. I guess it is to be expected from a 4-koma spin-off. Overall I still like Afro's style though.
The only character focus is on Homura, but since it's a comedy, she doesn't really get much development. The other magical girls get strange quirks and running gags and thus feel a bit one-dimensional. But overall this doesn't matter, because what matters...
...is the comedy aspect! In that regard, Homura Tamura both succeeds and fails. Comedy and enjoyment is of course subjective, but I thought the running gags were pretty funny at least in the first volume, and some of the situations were so bonkers, it caught me off-guard. The visual comedy aspect also sometimes worked its charm on me. However, it seems that the author burned out on creative scenarios some time after the first volume and relied a bit too much on "lolrandom" for my taste. The running gags are also run into the ground and get old pretty fast. The third volume steps up the game a bit again, but it still lost its surprise factor of many jokes - which is the most important part.
I can still recommend the manga to any Madoka Magica fans who want to see the characters go through some hilarious scenarios, but don't expect a masterpiece. If you aren't a diehard fan of the franchise, you should probably steer clear of the manga though.