Since this is a REO thread, I am going to go out on a limb and say everyone is going to say REO.
The REO vs Provari comparison has been discussed/debated ad nauseam for the last several years. It is an apples to oranges discussion. One is mechanical and one is regulated. One is a BOX mod and the other is a Personal Electronic Nicotine Inhalation System. Which one you choose depends on what you want to accomplish. Are you wanting to be a tootle puffer? Are you wanting to sub-ohm? Are you wanting to get within 30 nautical miles of water or go out in the rain? Do a search of the forums and form your own opinions based on what your end goal is.