Rather than invade the RX100 II to replace 4 year old sony CX100 camcorder thank you thedest for your post
Consumer camcorders can also have artifacts - not as much as a 7D, but they have it.
The GH3 and the 5DMK3 have a similar performance to some camcorders in that aspect - so they also have artifacts, but less often.
If you like the colors of the EOS M, you should keep it. For the price you want to pay, a little bit of M&A shouldnt be your main concern. You will have to learn how to deal with it. And its not that hard. Every camera have some limitations. You could buy a GH3 - that way you will have similar color reproduction and less artifacts than the EOS M, but I dont think its necessary.
The RX10 promises to reduce artifacts even more, but (in my opinion) it will be just like the GH3 and the 5DMK3 in that aspect, or worse. So, if you want to work with consumer stuff and you like most of what you get in the EOS M, you should just learn how to live with it.
Here are 2 new EOS M films of mine
The first is rather spoilt by focus hunt of some sort that i could not see in the lcd.
If i stay with the EOS M, not forgetting i have my HF-G30 for wildlife etc i will need to get the http://www.amazon.co.uk/Canon-Mount-Adapter-EF-EOS-M/dp/B008O0IE2Y/ref=sr_1_3?ie=UTF8&qid=1384180386&sr=8-3&keywords=EOS+M+LENS+ADAPTOR
which is expensive in itself.What lens would you advise,the The EF-S 18-135mm lens costs more than the EOS M