I am a firm believer in those sorts of easy rides, though I do not aim for any particular rpm. I just try to keep the cadence on the high end of comfy and the watts nice and low.
I did my first vo2 workout today and it went quite well. That said I had to chop a minute off my last couple of intervals because my arms were failing (lots of out of the saddle). So I am going to have to do pushups I guess.