I'm quite susceptible to RSI but it seems that, unlike others, my weak fingers are actually my thumbs instead of the pinkies, and this keyboard puts heavy emphasis to press modifier keys (enter, backspace - EDIT: ctrl, alt, etc were included in the list by accident) with the thumb. Within a couple of days I felt sore and could barely move my fingers. I then used the remapping software to move all modifiers to their usual places (as much as possible) and the situation did really improve.
However, I frequently switch between the desk and a laptop and always had to waste a couple of minutes to adjust to the different layout. The TEK _is_ slightly more comfortable but not enough to justify its high price for me, that's why I ended up returning it.
Additionally, the return process is long and tedious since they have a tendency to ignore the first few requests and they seem to respond only if put under pressure. I managed to ship back mine last week, after a monthlong attempt at gaining their attention.
I tried many keyboards during these years and in the end I think that switching to a mechanical keyboard (Unicomp EnduraPro) and from QWERTY to Colemak did 90% of the job for me. After that the law of diminishing returns kicks in.