Before I moved to Eugene, I also considered (Humbolt area cities) Eureka, Arcata, and McKinleyville as possible living locations. After a 5 days visit there, no matter how hard I tried, I just could not accept it. Sure, it has some great features (forest, ocean, liberal, sorta funky), but the negatives outweighed the positives. The negatives were rundown, grungy, and unkept...not just a little. Really bad.
As for Eugene, I think it has most of the positives of that area (except the ocean is not so close here...hey, fewer tsunamis...) and some of the grungy feeling in certain areas, but only a little. Many areas, especially in the south and southwest parts of Eugene, are really green, laid-back, and beautiful. Fairly neat and tidy too. The people here take pride in their city, and it shows. Of course, there is a grungy, fisher-price-toys-in-the-front-yard, rusted-car-up-on-jacks segment of residents, so you need to avoid the areas they tend to live in. (One of these days I want to put together a summary of various Eugene neighborhoods with pictures on my website, but until then, I suggest you take a look at
this other thread and, of course, drive around Eugene yourself...it's pretty obvious which areas are nice and which are not so nice. Fisher-price-toys-in-the-front-yard plus RVs/boats-in-the-driveway are dead giveaways.)
To compare it to Marin, I would say that Eugene is a bit more rustic, and obviously the real estate is much more affordable here. This is good news, but also keep in mind that there is a wider mix of economic classes here because of this. (See above mega-hyphenated-words...hey, that's ironic!...more hyphen-mania below too.)
Most importantly, Eugene has about 1% of the fake-smile, spray-tan, Starbuck-y, leased-BMW pretentiousness of Marin. On the surface, Marin has a nice clean Stepfordish quality, but if you scratch the surface, it is pretty ugly underneath. With Eugene, what you see is what you get. You might not like what you see 100%, but there is nothing hidden or fake. (On the other hand, since you are from Marin, you may think my description is insane, so feel free to correct me...I have only been to Marin a few times and had some college classmates from that area...but I grew up in a similar area).
Re schools: No idea. I'll let someone else answer that one.