My experience with dogwoods - C.mas, I've only sampled unnamed seedlings - fruits are very tart & astringent until 'dead ripe' - I like 'em, but many folks don't; C.kousa - the ripe fruits contain a pleasant-tasting, somewhat grainy pulp, with a flavor reminiscent of pawpaw(to me, anyway). I've not had many folks I've shared kousa fruits with who really liked them - but most don't care for pawpaws or persimmons, either.
Mulberries - hard to beat Illinois Everbearing, though I don't know for sure how it performs in the PNW - long bearing season(early June-late July, here), large berries with great flavor & sweet/tart balance. Collier & Stearns are also very good producers with good flavor; I've been disappointed with Wellington. Pakistan, Shangri-La, and some of the other large-fruited M.alba selections might also work well for you in a zone 8 setting.

I have a white mulberry and a weeping mulberry. The white mulberry has been a very poor producer, but is in a part of my 2 acres that is hard to reach with a hose so it hasn't had a lot of water. The weeping mulberry has small berries but nice flavor and shape. I've had a Cornus mas for several years but no blooms or fruit yet.

I guess after the apples and pears blueberries are my favorite fruit, followed closely by raspberries.