I've used both......extensively. Like any mod, they each have their place. I quit smoking on a vmod so I can't knock them.
I never held my vmod upside down to vape. I did hold it sideways like drinking out of a glass once in a while. It is gravity fed, so once you do squonk the bottle and get the
juice up into the atty chamber, you can vape for quite a number of hits before having to "feed' it again. There is no tube. The atty chamber design is interesting and works to keep any juice from leaking. The vmod is very ergonomic, it fits great in your hand, esp. if you get a rubberized cover for it. The vapage hybrid atties are very very good. The vmod2.0 is so tiny, it's really a great little stealth mod, but being 14500 you will change batts often. The XL is larger and takes 18650. Customer service can be spotty, either they are wonderful or a total fail, depending on the day. Chassis is plastic, so limited lifespan, but i had mine for well over a year, then sold it so...you do get a warranty
REOs are the yardstick by which to measure all other bottom feeders IMHO. I don't think they are expensive at all, given that you will have a metal reo "forever". That is because you can buy a rebuild kit and pretty much fix anything that goes wrong with it. The customer service is the very best in the
vaping world, and that is why they have such a great following. They are made from solid block of aluminum, so they aren't going to break. The following they receive is well deserved.
As for vape, a 3.7v bottom feeder is a 3.7v bottom feeder. You put a LR atty on there and you are going to get the same vape pretty much.
If you are gong to use RBAs then vmod is a little harder to accommodate that, given the way they are built. There are workarounds.
If you are not sure you are going to like bottom feeding, then get a vmod as it is a great intro to BF. If you know you like BF and want a forever mod, then get the REO.