The differences between the GL-100 and the GL-200 few and far between. The GL-200 offers fast printing, more borders and a larger screen whereas the GL-100 has two fonts but won’t print onto 3.5mm tape sizes. The GL-200 also comes in kit form (also known as VP or Value Pack) including the UK mains power adaptor and a hard carry case. The GL-200 and the power adaptor separately could cost £5 more and you don't even get the case for that price!
Whilst the GL-200 is still a current model, the GL-100 has been outgrown and been replaced with the GL-H105. This newer model can also be looked as a replacement for the GL-200, as and when that time comes, with all the same features, a faster print speed, and 2 extra borders. There really isn't much between them but using the printer is what it all boils down to. The layout of the button and functionality of the printer has been improved making the GL-H105 easier and more intuitive to use.