SPDs is such a system that the cleat has almost one position and the thing floats a lot, easy to work with that the users get used to them and from spd to look there's a lot of difference specially when the look cleats are in the wrong position.

Dunno if anybody said this already but there is a detail... with look pedals you need to get the angle of the cleats right or you will have problems engaging the pedals IN or you step out of them by accident or the other symptom is that you cant take the feet out of the pedals because the rotation angle is not enough.

Check out the position of the shoe (feet) when you are clippin' in. If you are doing an angle and the cleat is straight in the bottom of the shoe the entry angle is wrong and then you will have problems. Easy to find out tho... stand up and look at your feet, if your feet are in the position 1:50 PM and not in the position 12 o'clock then you have to correct the cleat angles to mimmic that in the pedals, with spd you dont have to do such adjustments because the pedal kind;a float more than the looks. Just small changes like 1 degree or 2 and then test untill you get it right and comfortable, sure unclip will get easier aswell.

Hope this helps.