Went from clips and straps to original Look clipless in 1986 and had no problem transitioning to the clipless or going back to clips. Around 2005 I tried Wellgo SPD and had a terrible time trying to find the spot where the cleat would engage the pedal and usually had to move my foot around a bit to get it to clip in. Also had a number of tumbles when I couldn't get my foot out after a sudden stop with foot at 12 oclock. Went back to Look style clipless.

Apparently the problem with SPD is that i still try to tip the pedal back so asto engagethe cleat the same way I do with clips and straps or the original Look style pedals and cleats.

If the setting for release is light it seems that most people using clipless SPD who've not used clips and straps have no major problems getting used to SPD.

Cheers