I have also used the open sided sandwich attachment and it is awesome. It melts the cheese without making a mess. I have also cooked sausage and salmon on it and it comes out great. Just like cooking on any grill, you just have to watch the temperature of what you are cooking so it doesn't get overdone.
I have had George Foreman grills in the past and have never used the waffle plates. I did this time. You have to be careful not to overfill the plate or you will have a mess to clean up. (speaking from experience) However, they came out perfectly.
Clean up is typically easy because you can remove the plates with a touch of a button and pop them into the dishwasher. However in my experience, they don't always get perfectly clean, so a trip to the sink for a quick rubdown is sometimes necessary.
The power cord is pretty short, but it works for my needs. Also, while this unit is bulkier than my old George Foreman grill, it takes up less space when it isn't in use. It can stand up and be moved close to a wall (see top photo). It takes up much less space than my Kitchen Aide Mixer or any number of devices I have in my kitchen. Just make sure you wait for it to cool down and clean the plates before storing it.
I love this machine. The ability to control the temperature means I can cook pretty much anything on it. This level of control was not available on my prior George Foreman grill, so I am very happy with this unit. It has become the most used device in my kitchen. I have used it for breakfast, lunch and dinner and it has never failed to impress.