I use circuitstudio daily, and looked at circuitmaker as a package to introduce some folks at our local hackerspace to.
If you completely ignore all the cloud aspects they're extremely similar with a change of colour.
However you can't ignore the cloud aspects. The biggest thing with the cloud in CM that turned me off is it only allows you to add components to your projects that have come from their server. So there's no such thing as a local library of components. When you create a component, you have to upload it to the community for anyone to use before you can even drop it on a schematic.
For me this is a complete debacle of a situation and has lead to the community being proliferated with useless, untested parts created by people who don't really know what they're doing. I'm a big fan of OS, but there's no way I want to put out a symbol/footprint for a component before I've been able to build the prototype and know it's correct.
CS is basically the same software but has the same local storage (or use your own SVN) and library management as Altium Designer, which I personally like.