I've not used one personally, but I've seen and handled one. It's very well made, but pricey.
The biggest disadvantage is that it's European-style, in that it is designed to be used with a 30mm copy ring, but a 14mm bit, not 1/2". That means cheap, disposeable cutters are not available to you.
If you always cut really good quality worktops, then it may be worthwhile getting the Festool 14mm replaceable bit cutter. If you're cutting cheap crappy worktops then you'll wreck the blades in no time. Doesn't matter how good the cutter is if the chipboard has scrap metal in it!