I have had a Samsung C49RG9 for about 2 years now, and I love it today as much as the day I got it.
I do find myself wishing for a couple of things it can't do, however.
I use PIP often to put a linux box on 1/3 of my screen and Windows on the remaining 2/3. It would be absolutely wonderful if the following were possible:
1) Add software that let's me control the monitor split without having to fumble with the tiny hardware joystick.
2) Add built-in kvm support so I don't have to run software like barrier. Barrier is awesome by the way, but it doesn't always work and can be frustrating occasionally.
3) I would like to do a picture-in-picture split with the main computer in the middle in front of me instead of offset to the left. Over the course of the day, it hurts my neck to have to look more to the left so much. I don't know exactly what this would be ... maybe a PIP option to have 1/4, 1/2, 1/4?
Sometimes instead of PIP I use VNC to control my linux box, but it just can't compare to the performance of PIP. What I like a lot about the VNC solution is being able to move the window around on my screen, to minimize it, and resize it, with autoscaling of content.