From the looks of the other reviews, I'm definitely in the minority here. But ignoring that fact...
I was expecting for this to be fantastic, introspective, and altogether beautiful but my feelings while reading this were lukewarm. I was as satisfied as one may be when they go to a restaurant with nothing but a picked-over buffet table at 8 in the afternoon.

Story: 7
It's a short manga, so there isn't much to say beyond what is already in the premise. There are some things that I would have preferred to have been resolved (who is Shino, what is Seryou's brother like, etc.) and for other things to be expanded on (archery club, Seryou's questionable attendance, his week-long girlfriends), but unfortunately these things never are.
I wasn't too crazy about the dialogue. There wasn't anything wrong with the scanlations I was reading; the dialogue was just too lackluster. A lot of simple sentences.
I like how their entire relationship wasn't sexual. It's very frustrating when two people meet and decide to solidify their relationship by having sex or whatever. In this case, it wasn't even about being gay, bi, straight, etc. it was just two people who love each other.

Art: 6
This art was comfortingly familiar because I had previously read something with the same artist, Torikagosou no Kyou mo Nemutai Juunin-tachi. However, it wasn't as good in this manga. While the art still had that soft, sweet quality about it, the proportions of people were off- small heads, too-long arms, etc.

Character: 5
Shino is supposed to be a guy with a beautiful face but a disappointingly taciturn personality. Or at least that's what everyone kept saying...His "terrible" personality was really blown up. For example, after getting a bulls-eye in archery, he does a little fist pump. His teacher yells at him for his "vulgar" display. Is there some cultural thing that I'm not getting here, or...?
Seryou seemed like a bit of an airhead. I'm not sure that he thought through the whole "date a girl a week" thing, nor am I sure why he was so hooked on finding love.
Overall, the characters weren't shallow, just not developed enough.

Enjoyment: 6
Not the worst, not the best. Seven Days is worth reading though because of the unusual circumstances that Shino and Seryou's relationship is formed and the basis that it was formed on.