It really depends on what your going to use it for. It's necessary if you want to use surface mount parts with a fine pitch. Or anything with a really wonky foo

It really depends on what your going to use it for. It's necessary if you want to use surface mount parts with a fine pitch. Or anything with a really wonky footprint. I find it's quite useful for the mechanical properties, being able to size it to the exact enclosure and put mounting holes where needed. And you can print cool art on them for the extra wow factor :) I particularly like OSHpark's after dark board for this, drawing in the copper layer looks fantastic with them. In general I find it's not worth it for a weekend project but if you are going to be looking at it often and want it to last, definitely worth it.