Like always...I use any method I possibly can to make things a bit easier when cutting circles!
Especially when a model has many many of them ( Tank bogies and the like come to mind as well as the way I construct wheels and tires). I do use the circle cutter ( USA name Compass Cutter, mine made from X-acto) and like it very much, Pros- works great for repetitive circles of the same size and keeping everything consistent Cons- smallest circle is about 7mm, when cutting thick stock .5mm up , for wheels etc. you need to slowly cut through the material or will tend to start to spiral cut outwards...the one I have you can not move the blade or center point in our out, so on smaller cuts on thick stock cuts a slight bevel as the blade and needle are not the same length ( BTW this one plastic but is a very in-expensive cutter ) I would recommend if you buy one make sure it is metal and the blade can be moved down to match the length of the needle, also if you are cutting many circles but they do not have radius points in the design this won't work well for you, it can be done but not easily or quickly!
Above...circle cut out of 110lb card stock...very simple to do and gives a very clean result even with this plastic compass cutter! Below... second cut using same radius point to cut out smaller circle but also what could be the rim of a wheel or something similar! ( I could never get this quality of result cutting 20 of these out with an x-acto)
Below... I used the very small punch shown in top pic right of the compass cutter to punch out several holes, or the punch-outs ( which I use) can be used for bolt heads or rivets and the like!
The leather punches will do a variety of hole sizes either as cut outs or for circles, very hard to line up on a printed model though, but for scratch building a great tool! You must make sure that the punch has a sharp cutting edge though, since they are for leather they are not usually as sharp as needed for paper-craft! I use the plastic credit cards that come in the mail and a small rubber mallet to tap out the holes and needle files and diamond hone to keep them sharp!
When doing odd curves or circles that all the above will not do, there is nothing better than my old Olfa or X-acto knives!
Hope this helps!