I picked up a used platinum M5 HT because I really wanted to try the HT shape. I have really liked using the FGP2 but you know, always searching. Well the head weight felt heavier on the platinum and I had a really hard time making putts with it. I weighed both putters and they was only an ounce different between the two. Not sure if that was throwing me off or what? Gonna have to move the platinum and maybe just try the black HT mallet.
m5 HT has the shaft placement more towards the heel whereas the FGP2 is a near center shaft. The "feeling" that you are feeling could be how the FGP2 putter head is coming back to "square at impact" easier or automatic. You do not have to do any manipulation with your hands. Whereas the m5 HT the putter head wants to open up just a hair at impact therefore you have to "manipulate" your hands to make it work. Either you have to turn your hands more or have to pull across the stroke to square up the putter face. Therefore you might make some and miss some.
FGP2 you might be more consistent with your alignment and stroke and have a better outcome. Hope this make senses.