I've two Rotozips, an early one and a later one. Think of it as a small router, good for cutting-in around electrical boxes using the plunge function. I have one of the attachments which works well for small spaces and light material. Cutting-in for ceiling luminaires is very easy, I used it on an old plaster ceiling, and w/a helper using a shop vac nozzle, the amount of dust was minimal. I now have a surround to accomplish the same thing, but as I only work on things in my home, I don't need it much.
A Rotozip is a worthwhile tool to have and to use. I thought it was a foof-tool until I used one, and for what it can do, it's sturdy, works well w/a minimum of fuss, and it does have utility. If you use it, I think you will find it has a place in your tool inventory.
I don't think it's a replacement for a Dremel, but I've been able to use mine to make jobs easily-done that would take more work w/another tool.
I also have a multi-tool, and like it for what it can do, and a baseboard cutter, but since I don't do much flooring, it doesn't see much use.
lol. What i can say about it if you haven't actually handled one is it's like a dremel on steroids and feels VERY sturdy. I'm actually thinking i may just ditch my dremel (out of my toolbox) and use the dremel for wood carving and such. It had been my cut off wheel of choice since i don't cut anything too thick, but it's nice to have the large cut off wheels on this like i would using a cut off wheel at work. I wonder if they sell a sanding attachment that would fit this. They have a chart of compatible attachments on their website but i'm wondering what bits, wheels and other attachments besides the ones on the chart will fit. I'm also wondering if the DM4-10 is able to cut plywood and such. Any insight would be awesome! I'll be lending it to someone while they remodel their home so i'd like to get all i can to make life easier.