"Even so, with a smallish population of users and the spammers still figuring out how to operate, G+ has some serious usability problems (like you can only see 2-3 items in your stream at a time on a high resolution display) and it's already getting kind of spammy."

My feed has interesting/funny comments and links... because I just put interesting and funny people in my circles. And I don't consider the fact that I can only see 2-3 items on a high-res display bad if the quality of the content is higher than other sites I visit. There are some blogs whose index page have the same issue and I'm fine with it because I know that every single piece of content posted is well worth the surface area.