The great thing with them is they are quick and portable and a damn side easier to get out the van than a table cutter. The down side is the battery runs out quick and you only get one with it and you have to be very careful with the blade. By far the better cutter is the Makita 4101RH which is a hand held wet cutter but then you are moving into the £300 bracket for one so I would probably go with Daves advice and get a table saw
Kev