It's technically Sefardi, but it has many columns of the Sages of the Ashkenazi world too. It even contains a "comics" serial about the life of Rav Aharon Leib Shteinman ztz"l.
It's hard for me to read the whole thing cover-to-cover because it's in Hebrew, but I enjoy the halachot and the stories, especially in the section for women. (It also has a children's section.)
But in the general halachah section of Bamidbar, they presented a Q&A with Rav Bentzion Mutzafi.
One question was about the significance of the Mussaf prayer on Shavuot.
Rav Mutzafi's reply:
The Mussaf prayer on that day is of tremendous significance.
Imprinted within it is the holy service of all the days of the Sefirah and we are written in Sefer Hazichronot [Book of Remembrances].
And we merit to receive the level of an exalted spiritual soul for the entire year.
And my father, my teacher z"l prepared himself with eimah & yirah [reverence & fear] for this prayer.
It's amazing to think that a really geshmak Mussaf on Shavuot can earn yourself a whole new level of soul for the ENTIRE YEAR (what's left of it, anyway — which is actually a lot and means that you enter next year on a much higher level than you would otherwise...yay!).
Needless to say, some people might not be able to daven Mussaf Shavuot. Maybe they're busy caring for their family &/or guests or maybe they're not feeling well or some other reason.
If you have no other choice, just ask Hashem if He could please include you in the Mussaf davening of Am Yisrael.
You can also say something heartfelt like, "I love You SO MUCH Hashem — thank You TONS for the Torah!" and then ask Him to accept that as your Mussaf.
Yeah, I just made that up, but it's based on related traditions, like the prayer said at the end of saying Tehillim or before saying Tikkun HaKlali and other ideas mentioned in Chazal.
Also here is an amazing transcript of a class by Rav Itamar Schwartz:
Shavuot: Give Yourself Your Real Needs (3 Kinds of Love)
The transcript recommended at the end of the above link can be found here:
Fixing Your Water: The Desire to Love & Be Loved
(To my mind, this is an all-important read with or without Shavuot, and regardless of whether your personality contains a large degree of the "water" element or not.)