for value and ease of use a MTB shimano SPD is a great way to go...

for hot spots... better shoes or better cleat placement can help HUGELY... I picked up some A520's recently for the extra support they give for the somewhat flexyer SPD sandals i've been using...

as for single or double sided pedals... having started and spent almost 2 decades on two sided SPD it was a little akward getting used to the single sided pedals... I never had to think about clipping in before but now I need to make sure my foot is hitting the pedal on the correct side... not a real issue on the road but I can't imagine trying to use them on the trail where clipping in and out isn't so infrequent lol