Hi Giovanni,
I've had that Vk8m module for many years now. I just love the tonewheel emulation and the Leslie simulator. I also LOVE having real tactile drawbars. It's great during live performance if I need a little tweak here or there. The D-Beam controller is great for turning the leslie fast/slow at the wave of the hand. People look so quizzical when I do that. The Motif and the T4 cannot match the Vk8m Hammond sounds. I wish they did so I didn't have to bring so much equipment, but hey, its easier than lugging a Hammond/Leslie around.
It's a great investment and I've gotten my money back fourfold.
If you do get the Vk8m, look into getting this upgrade pack from soundside
http://www.soundside.de/shop/vk8upgradepack.htmIt adds some great voices (not samples)
Best of luck with your decision!
Regards