What do you want on the Deluxe that's on on the Pro or A? Honestly most of the Asus boards seem pretty much the same to me.
Actually I am not sure of the full specs on the X99-A or X99-Pro yet.
I think they all will probably have a very similar PCB layout. There will be some differences in cooling solutions, physical PCIe port configurations, WiFi 802.11ac + BT 4.0 (probably wouldn't work in OS X), number of fan ports, number of USB ports, number of SATA ports, number of SATAe ports, supported length of M.2 modules, support for dual M.2, number of Intel NICs, possibly a different power subsystem,...and so on,...
Admittedly not all of it is important to me,...
Another possibility for me would be to simply purchase:
Core i7 5820K
Asus X99-A
8GB DDR4 2133
Or I could take another look at the Gigabyte and ASRock boards,...
I have heard that Asus was supposedly going to drop the prices of their boards by ~5 to ~10%,..
Either way it would help free some cash for the purchase of a new iPhone 6 Plus.