We have a Doosan H2017. It is the biggest one they make. We added it to our toolroom fixture building machine so we could get some unattended runtime at night. It does a decent job but we have had a lot of intermittent communication issues. The controller to pendent and controller to robot cables are super susceptible to RF interference. We have had to go to extra lengths to isolate the cables. The problem is the built in Modbus TCP master times out super early and then doesn't automatically reset. The ABB's have pages and pages of control options and settings, the Doosan is rather limited. As far as the robot, it has been great, no issues there. FWIW, we have 8 ABB robots and my comparison to the Doosan is based off that. For advanced programming, the Doosan sucks compared to the ABB's. For entry level to moderate programming, the user interface is very good. The "conversational" style programming is super quick and simple. Before we added cylinders for autodoor I was using the robot to open and close the door. It literally took like 10-15 minutes to program that. You just manually move the robot to each point, record the point and then move on. the down side is, the collaborative force sensing kept tripping out when the door had chips on the rail. It would cause the door to bounce and then over load the robot. We also ended up adding a floor area safety scanner and shutting off the collab force sensing.
Short summary, for entry level/simple applications I would not have any issues with the Doosan. For more advanced automation I would go for an older, more fully developed programming language/system, robot builder.