I've just gotten back into riding after a long time and have a few 20k rides under my belt now, feeling better everytime I'm out. Right now I'm using running shoes and regular pedals on my Giant FCR2. I find that my feet are moving around a bit as I'm pushing forward at the top of the stroke (that one really burns) but it's more that I'm pulling back at the bottom of the stroke that's causing my feet are moving a bit. I used clipless pedals before and even after 15 years it seems old habits die hard.
After spending more on my bike than I'd planned plus there are some accessories that I need I'm not really anxious about having to buy cycling shoes soon (I can use my old pedals I think), though I would like some proper shoes at some point. I'm wondering if there is any benefit, fitness wise, to pedaling through most of the stroke rather than just pushing down all the time. If there is then maybe I'd put the shoes in a little higher priority. Also I'm thinking maybe it wouldn't be a bad idea to get them sooner than later before I loose the "habit" of pedaling all the way around.