Spinsaw opinion

Do you mean a hole saw?

No, something like this;

It is not the tool I would use to cut holes in MDF. You have not indicated what size holes, how accurate, etc. A router will give the best cuts. A jigsaw or hole saw will give decent cuts. ______________________________ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

tool is commonly called a rotozip here - basically a small frame plunge router. They spin at very high RPM, just like a router. With an appropriate bit, they will cut MDF, plastics, even sheet metal sandwiched between wood, very cleanly. However, be aware that you need a screw hole in the center of the circle to anchor the circle cutting attachment - not not an issue if your end product is the hole, could be an issue if its the disk.....

Will it cleanly cut 3/4" mdf or will it leave rough edges ?

Yes - I use my router on MDF regularly, and the high RPM combined with a sharp hardwood bits cut very cleanly indeed, cleaner than a bandsaw cut. You may have to buy some different 1/4" router bits (cutting tools), depending on what comes with that kit. You can also use round-over, cove, and other profiled cutters quite nicely on MDF as well.