Aside from Natsume Yuujinchou, Tsugumomo is the only other anime I have been following studiously week in and week out. With a new studio Zero-G helming the production, I was unsure what to expect. But with the catchy theme songs, especially the ED, I was immediately hooked to watch more. That is why I believe that having strong theme songs inevitably makes an anime much nicer than it really is sometimes. Music is important, and theme songs are important. Tsugumomo uses a classic approach of having an upbeat OP and a slightly melancholic ED which is a tried and tested formula that works by keeping people watching.
If I were to only say that Tsugumomo was only good for its theme songs, I would be doing it a huge injustice because as you watch, you develop strong attachments to the main characters. 12 episodes is definitely too little for a manga that has been serialising for over 10 years. Surely, there is sufficient material for more, but sometimes, having too many episodes for the sake of it becomes slow and torturous. Watching Tsugumomo, you can tell that this is a carefully written anime that you can hardly spot any unnecessary scenes. The pacing is just impeccable. The anime reminded me a bit of Kaze no Stigma, Shakugan no Shana and even Inuyasha.
Aside from the pacing, what makes Tsugumomo so good is that it has everything in it. It is an action genre with fantastic action scenes, but it also leaves sufficient time for ecchi when it is appropriate without interfering and taking the spotlight away from the story. It has drama at appropriate times for you to develop an attachment to the characters. Finally, it has comedy all around. This is definitely an anime that anybody can watch, regardless of whether you are a particular fan of a certain genre. It is very mainstream, except for the ecchi, and easy to get into it. So if you are looking for a fun anime that has great action and good chemistry between the male and female leads, this is the anime for you.
TL;DR: Tsugumomo is an anime that has very good pacing despite having the tall order of reconciling multiple genres together in action, comedy, ecchi, drama, and finally, it has very good theme songs. Watch it and you will not regret.