For some reason I did not like the bottom part of Darth Vader’s mask. It looked like a flexible rubber pull over to me. And Vader’s walking stride (gate) was noticeably different. Also the voice seems to have been processed quite differently as well.
I agree with your observation of his mask and thought it stuck out like a sore thumb. But, after pulling up some images from the OT, it seems very similar to this go around. I think what was going on in the OT is how he wore his cape. If you look at a few different scenes, often times his cape was covering a good portion of his chin/neck. Also, I think lighting had a lot to do with it. Im with you though, it still bugged me.