I have run SPDs and Time ATAC pedals. My knees seem to prefer Time ATACs. I found SPD pedals needed to have the spring tension wound up a fair bit to stop my feet popping out (which also restricted float, AFAIK), whereas I never recall having that issue with ATACs.
Currently running Speedplay Zero road pedals (a truckton of free float) on the road bike, and the walkable cleat covers. not awesome for walking around, but definitely less skatey and sketchy than old look and Time cleats I've used.
Time ATAC should be fine for your road bike if you are not racing, IMO. If you fit the cleats in the regular way, there is 17deg release angle. if you fit the RH cleat on the LH shoe, and vice versa, you get 13deg release angle IIRC.