Wall chasers are very simple machines and make the job very easy and quick. If you are just doing your own house and not working with it day in day out you won't need a complex one or any sort of accessories. You probably won't go through more than one pair of discs either but if you do never replace just one of them! I have got a cheap Erbauer chaser which is fine for occasional use. Did all the slots in my house in about a day and a half which is much faster than any other method, that's all slots cut with the chaser and all box chopping done with an SDS sinker too. The guard is good enough and catches all the debris, the cut width is adjusted by packing spacers between the discs and the depth as you would a circular saw. The thing to watch with them is sometimes all the bulk of the machine and extractor gets in the way of cutting the slot right next to something but this is normally just for short stretches when you can finish with a slotting chisel in an SDS easily enough. I would say that what you do need to spend money on is extraction. Get a decent tank vacuum, one that automatically powers on with the tool so you can't forget it. Karcher ones are great. Without extraction chasers are horrific, they produce incredible amounts of dust. Get good extraction and clean the filter regularly. You will also need very good ear defenders and eye protection. Some chips and grit do escape the machine hood sometimes and it takes you by surprise when they sting your arms let alone your eyes. Oh and always use both handles, they try to climb up out of the slot as you push forward if you don't keep them pressed down.
Edited by Dan, 29 December 2014 - 04:01 PM.