I've been using RCS for a while now. I work for a major OEM and have developed new malware removal techniques for our frontline technical support. While Sysinternals is the cornerstone of this process, RCS is the primary AV / AS used for a number of reasons.
Firstly, since it is made by the people behind herdprotect, and the founder is known for his development in network based detection, it is safe to assume this uses the same engine(s) herdprotect uses, which is somewhere in the number of 68 I believe. This is proven, without official word from Reason themselves, by the fact RCS detects so many false positives.
Secondly, it completes a quick scan quickly. I guess that's to be expected, but I want to add that the quick scan is also pretty thorough. In my experience developing and testing these new processes that use RCS as the AV / AS of choice, the quick scan has historically removed most threats on customer's computers.
Thirdly, the additional features such as program uninstall and remediation tools are invaluable.
Fourthly, and this is something more geared towards our company, since the terms and conditions are friendly for a technical support environment. Obviously our company doesn't use RCS commercially and the customers always accept Reason's terms and conditions. This just makes it easier to use in a setting like we do.
There are some downsides to RCS.
Firstly, Being cloud-based, without an Internet connection or on a corporate network, you can and will run into issues with the tool.
Secondly, since RCS is rightly advertised as a second opinion scanner, it doesn't have a high detection rate. This is at least based on others tests. I admit I haven't tested it with own samples yet. My job role requires my attention elsewhere from time to time. I will say this, I've used RCS to clean dozens of systems, and each time that low detection rate has almost completely cleaned the system.
Thirdly, this AV / AS has a high, very high, false positive detection rate. This is likely attributed to the fact RCS likely uses the same engine(s) as herdprotect, which numbers somewhere around 68 I believe.
I want to allude to a comment by Mark Russinvoch, the creator of the Sysinternals Suite, and perhaps a genius when it comes to malware, that newer malware is simply going to become undetectable using standard detection methods. RCS, with people like Andrew Newman, will definitely become a much better AV / AS with higher detection rates. 22% isn't bad, by the way, when you consider Moheeb Rajab tested 4 major AV / AS engines and found they find around 35% of the threats. These are major engines that have been around for a long time with hundreds or thousands of people working to make them better. RCS will likely get its time.
I don't know. I don't think RCS is the future, but as it is right now, it's quite good. I do highly recommend it.
**EDIT** - I know I left out some links to sources for the comments by Mark and Moheeb, but you can find them using Google. Mark's comments are in the TechEd videos, while Moheeb has a paper published through Google and the University he works.