platform pedals make my feet hurt so for me clipless is a necessity. after trying multiple mechanisms i decided i love spuds. i even got rid of the spd-ls on my road bikes and replaced them with 280 g A600 road bike spds:

i love the fact that i now have the same clipless mech on my 37 lb shopping bike and my 17 lb race bike.
i often wear half plate spd shoes when i need to walk around and don't want to carry extra shoes. for me the lack of a full plate make them just as comfortable as normal shoes. i particularly like the ct-80s:
for commuting and sport i prefer giro carbide (or m077s). i tend to buy multiple pairs since i almost always crack the plate after ~2 years of use. (i hate ratchet shoes because i always break the clasp.)