Never used Mal's, but if you have a hundred products and growing, it sounds like you are ready for serious e-commerce.
Fantastico can work for fresh installs, but I understand it wants to put Zen Cart in a subfolder, which is not ideal - the store should be immediately accessible in the domain root.
The manual installer is almost as easy (there is information you must enter in any case), and you will start with some idea of what is happening. You will need to use your server hosting control panel to make a new database and user before installing Zen Cart (your host may be willing to do it for you). The steps are generally simple and covered by the Zen Cart documentation and tutorials.
If you get stuck and can't find answers in the tutorials or old forum threads, we are here to help.