I have used both with good results but you open a can of worms when you posed your question. there are good plotters and good computer systems. So much of the answer depends on what you are willing to spend and how much you want to do with it, as well as where you will use it. Bigger boats with a console where you can mount a laptop without worring about it getting wet or in some other way damaged are what I would perfer. If the laptop were in a smaller boat outside you need consider weather and installing so the wire and cables are not a trip hazard, maybe a small hand held plotter or mounted plotter might be better. It must be at the helm or very easy to see from the helm having a unit that would work below is a convience for making plans. For a lot of reason the computer based systems are what I would perfer to use. The big concern would be where and how you are going to use yours. Caution.............. make sure you you are able to see what every you buy as a lot of laptops and some plotters will "wash out" in strong sunlight. Maybe think about what and why the commercial operators are using (majority use computer based) may help you decide.