Oregonian here. I've lived all the places you mentioned, and then some- but the majority has been Eugene, Corvallis, and Portland, so I'll address those. You said you've been to Portland, so I'll just use it as a comparison point. 9% income tax is not fun, but no sales tax is great (if nothing else, no mental math in stores). And it's true- it's beautiful and lots to do outdoors.
Corvallis- a weird lovely bubble of a place. Very college focused, but a small town feel all in all. Very few "chain" stores- everything is mom and pop, and the town has a history of denying big stores opening, like WalMart. Something like the second highest per capita rate of advanced degrees in the US. Very bikeable and walkable. Not too much crime except stupid college things- public urination, bike theft, vandalism after football games. Not a ton of industry, and it can be VERY hard to find a job. Too many college kids willing to work for any level of pay while in school. Tons of hiking trails right by town, with McDonald/Peavy/Marys Peak. Relatively expensive compared to some OR cities, but not as expensive as Portland.
Eugene- It really depends on the area you're in. South Eugene is a world apart from North Eugene/Santa Clara area, which is a world apart from Sheldon/Coburg Rd area. Very much "duck fever". Rabidrabidrabid fans. Starting to have some renewal and new businesses coming in- thank god because otherwise the downtown is a sad shell of the 70s. Hiking isn't as readily accessible as Corvallis, but IMO the access to the cascades has more to offer. Very bikable though, although it varies a bit depending on the area you're in.
Tons of food culture in both Corvallis and Eugene. Farmers markets and lots of local sourcing in both places. Restaurant scenes are pretty good, although I'd put the balance to Corvallis having more to offer there. Eugene has a lot more standard commercial things you might want- Target and Costco and Walmart and the like. Eugene has the Hult Center, so some shows come through (much more than Corvallis), but if you want really big name/big production stuff, you have to go to Portland anyway. But Corvallis has TONS of free stuff to do associated with the university, and I always found it to be better advertised than the free stuff in Eugene. Both have great public libraries.
No matter what, if you want to do outdoor stuff, you'll need a car in Eugene or Corvallis (or a friend with a car, anyway).
In general, with Oregon though, downsides include: income tax, grey for months on end (lots of depression!), very humid in fall/winter (lots of mold! and allergies to mold!), tons of grass and tree pollen in the spring/summer (lots of allergies!), DEEPLY divisive political views- we have a really sharp urban/rural divide, so you get extreme politics on both sides, and never the two shall meet. Drug problems are big (meth!), and to fly internationally you pretty much have to drive to PDX (eugene has an airport, but it's got 1, maybe 2 gates). Oh! And field burnings- lots of asthma attacks every year with those.