I always have a soft spot for the manga version of Here is Greenwood as it's probably one of the first manga I've read. And since then to when I started the anime, still have a special place for it. The anime retains the same feel of the manga but it excludes some things (More on that a bit later). It's not overly exciting, complex or full of intrigue or any of that jazz, but it's pleasant and nice; and that's just what I expected, something to remind me of the manga and it did just that.
The synopsis will do you fine as most of the events are episodic in nature. The only time it goes into something like an arc is in the last two episodes, which goes along with the arc in the manga. As much as I liked the first four episodes (Especially the movie), the last two I particularly enjoyed. It may be for the sapiness of it or because I'm a sucker for that kind of stuff (Resisting spoilers), but I really loved it.
Considering that it's a six-episode OVA from an 11-volume manga, it's reasonable that things would be cut; side characters that don't get any screentime, others not as developed, even a few secondary character's backstories get cut out. Some of the events are taken out, including a sports festival that's suppose to be inbetween the arc that's in the last two episodes. If it was longer than it wouldn't be a problem but it's still unfortunate that it's this short. But it's still something to see this actually get an anime adaptation.
As previously mentioned, some backstories of the characters are cut. But to be fair, it can be considered more than some. But what's there is nice, it's just that there could have been more. Even so, it retains enough to have the main and secondary cast stand out on their own with their own traits and quirks; from Mitsuru's quick-recovery face to Shinobu's older sister's hatred for her younger brother. What was especially touching was Hasukawa's resolve in the final arc; his determination to never give up and the backing he recieved from the residents of the Greenwood dorm, his brother and Sumire. Where they all banded together and that it was more than just a simple dorm.
It's nice to look at and although the characters look a bit dated, the backgrounds and much of the animation retain the good side of that old-school feel. Or simply that hand-drawn feel, which I loved. Almost like a painting at times. The music's nice, but not particularly memorable and the voice overs work; nothing exceptional, but they don't drop down to the level of being annoying which is always a plus.
I guess I would say to read the manga version of Here is Greenwood before you check out the anime. It has more than the anime and feels better overall but for me, I enjoyed the anime, regardless of what it's missing from it's original source.