We use the step in style as my baby thinks she is Houdini and has escaped from every over the head harness we tried, but either of the ones you posted should work fine.
I have been using the EZYDOG harness as well as there Cujo shock absorbing leash for the past few weeks and really like them both. The harness is very easy on and off. I did buy it on the large side as she is just five months old.