Im pretty much a newbie and Ive been running some Shimano M520's SPD pedals with Pearl Izumi Vortex's shoes. Havent noticed any float at all. The pedals have adjustable tension. I found out the hard way its better to start low and work your way up. High tension = cant get out.
Only complaint for me on the combo is my area is extremely rocky so it would have been prefered to have a flat rubbery sole but they work out alright. Great for hiking up muddy hills since they have nice cleets (not the cleet to connect to the pedal). Sometimes Ill slide off rocks because of the hard soles. The pedals are very good at shedding mud. You should have seen my shoes after my last ride, they are still real dirty. Then theres the obligatory adjustment period of remember to twist your heels out to get out but we wont go into that. Too embarasing.
Only takes a few times before you learn though.
Friend of mine has the same pedals but flatter/more rubbery soles (shimano M038 Mountain Shoe). When I tried them they were nicer for walking but my stiffer sole is better for power transfer and dirt/mud. Its all about riding though...not hiking...
Between the two I also noticed I like my velcro/ratchet straps more than his laces with one velcro strap on the top. I like my shoe being tight for riding. Took a little getting used to before I stopped getting it so tight I cut off circulation to my feet.
Pedals cost me $55 and shoes $90 (shoes were $20 off). Think my friends shoes were around $110. That was the price from our LBS. You can prolly find better deals online. Shouldnt be hard to find a good set for under $200 unless your looking for something real high end.
Theres what little infos Ive got.