Some of the key words I've read while skimming this thread are: Simplicity - Craftsmanship - Durability - Reliability - Performance.
I want to add a nother key word: Service. If the device ever gives you trouble, send it back in and Rob will get it fixed and return it to you quickly. He's one of the best out there with far and above excellent customer service.
I own a bunch of high end gear and I own a bunch of low end gear. I have favorites in either category. My tube mods have been being slowly packed away or given away. My plastic box mods are mostly given away now. My ego and ego-clone batts are almost gone. i have one left when I had handfuls of them as recently as just a few months ago. .. My REOs have completely taken over as my vaping devices.
They are reliable, durable, good looking, good performers, easy to use, and easy to maintain. Had I bought my REOs first, I doubt i would have ever purchased any of the other dozens upon dozens of PVs I've had.
My REO Mini allows me to carry nothing but one AA battery box with 1 spare battery and 1 spare bottle of juice inside. My REO VV Woodville allows me to be out all day without concern for juice or battery life, so I carry nothing extra with it. REOs are the most hassle free way to vape... and there is a little something in the product lines to suit almost anyone's needs.
Once you pick an atomizer you like and get a few batteries, you're all set for a very long time. I wish I had listened to the first dozen or so people who recommended REO to me. I got my mini on 11/17/11 and not a single day has gone by since then that I didn't use it. It gets used every single day. I bought my RVVW on 4/28/12. it is not only beautiful, but it is an excellent high performance, variable voltage, PV. Every day, no matter which REO I'm using, I fill the bottle, pop in a fresh battery, and go. I worry about nothing because there is nothing to worry about. ---> And, importantly, I know for a fact that REOs Mods stands behind their products. If something ever does go wrong, pop it in the mail and you'll have it back all fixed up in 2 shakes of a lambs tail. -- those events appear to be few, but the posts I've come across all praise Rob for doing such a fine and fast job of getting the unit fixed and returned to its owner.
The more time goes on since I got my REOs, the less and less I use any of my other gear. In fact, what was my favorite PV a few months ago sits with an empty bottle right now.