I do not like the Modern style.
I hate Windows 8 tile interface.
The current Modern style is very buggy.
Examples: Right now I cannot view it in Chrome. None of the tiles show up. The menu sidebar does nothing. Was this tested in Chrome at all?
When I switch to IE, I found that I cannot type into the Search field when I'm viewing the activities list.
I am quite happy with the classic version. Please keep it.
I realize this is a free service you offer, but I am seriously considering going somewhere else to track my workouts.