I would probably get the Venue 11 Pro. (funnily enough, the Venue Pro - without the number like 8 or 11 - is a Windows Phone 7 smartphone)
Specs can be comparable, but the Venue 11 Pro has a lower spec-floor. (it has an Atom model)
My thinking as to why I recommend this model:
Cheaper
Replaceable battery (this unit is infinitely easier to repair than the Pro 3, but that's reflecting more on the utter lack-of reparability on the end of the Pro line)
Laptop dock model (extra battery I think - however I think the type cover is hard to imitate with the Venue's flip keyboard cover)
However, the Pro 3 is higher quality IMO, has that kickstand (a big one), better design and feel and has a better pen. But I don't think it'll be worth it to me in the long run.