Sorry Brandon, I don't have access to the F2.8 but I can say I'm pleased with the F4 and with the 6D low light and F4 is not that challenging. Of course there is the bokeh issue but I use this WA lens mainly for scenes outdoors anyway. Any shots I've posted that are WA will be with this lens. The macro is handy and not useless as some have implied. The data is in this shot taken at 24mm. So far I'm not complaining and that deal you mentioned is VG.
Thanks for the input, Jack! I'll definitely add that to my consideration whilst I try to make a decision over the next couple of weeks. Keep up the great images, cheers!