I own a KP200S and just recently bought an SL200S. To make a play on words, talk about a "sound" investment! This system, by far, is the best amplifier system I have ever used. Being a professional musician, I've gone through more than my share of keyboard amplifiers over the years. Rather than place my SL200S underneath my KP200S as it was meant, I place my SL200S on the other side of the stage. I have have a 20ft MIDI cable that I use to connect it to my KP200S. This works out well for me in a number of ways: I don't have to play as loud to fill up a whole room; musicians who are on the other side of the stage can hear me better (I play in a lot of situations where the bands only want to run the vocals through the PA); I seem to get better, more even sound dispersion over a wider area and my audiences and customers really seem to appreciate this. No, they all may not understand what's going on technically like I do, but I sure get my share of compliments from clients and fellow musicians alike over how good my sound is these days. I read many reviews on these two products before buying as I ordered both units online - sight unseen. I'm from the old school and I like to see, hear, touch, feel, and play before I decide hand over my hard-earned salary. Ah, but this is fastly becoming a thing of the past in this new age of digital cash. Both units arrived in good condition and I took them out and used the same night of the day they arrived. What's good? The sound is phenominal! Controls are very intuitive. Every volume and EQ adjustment I make on the KP200S which I have right beside me is going to happen on my SL200S - remember, with the way I use it, my SL200S is usually on the other side of the stage from me sometimes by up to about 20 feet. Lots of people complain about how much these units weigh, but honestly this is not a big deal to me. I find it's no different than handling any other piece of equipment. A lot of people complain about it not having a headphone jack. Well, when I want to practice with multiple keyboards I just run them through a submixer and use the one headphone out to monitor all my keyboards at once. I don't think the lack of a head phone jack on my Motion Sound system is a negative. I own a set of subwoofers that I've used in tandem with my Motion Sound system. The subwoofer out is a great feature. When playing with bands, I don't care about bottom end as much - I leave that to the bassist, but when I play solo jobs where I really feel the need to use the full sound spectrum, the subwoofer capability is very nice. What I don't like: I don't like that when I adjust my sound on stage, it also affects the signal the sound man is getting. I'd like for the sound person to be able to have complete control over my volume in the main mix irregardless and independent of what I need to do to make my on stage volume comfortable. Overall, I'm very happy with my "sound investment." I like they way my Motion Sound system looks. It makes me look professional too. I like they way it sounds as so do the others that I play both with and for. Would I replace it with another Motion Sound system if something happened to what have? Yes. They're pricey, so thank goodness for insurance!