Mechanical sewing machines come with manual controls, while computerized sewing machines usually have a little touchscreen or digital control panel to let you change things like stitch type and size. Computerized machines can also often be connected to computers and the internet to download new designs, making them more flexible. In terms of which is easy to operate, it actually depends on the person. Tech-savvy people tend to enjoy the flexibility of computerized machines, while others can find all the computerized features a bit too complex and prefer a more traditional, mechanical machine instead.