Shimano M324s have a grippy platform side (better than the A530s) and a clipless side. However, I only use them in the winter when I expect to use winter boots. Rest of the year on the commuter, XT pedals (M780).

Improved power transfer, feet not slipping off the pedals and climbing out of the saddle are primary advantages.

Non-Shimano SPD-clone pedals should be avoided. You may have good luck with them, but pedals are not something you want to go cheap on.