Let's try to demystify the HIPS component of Comodo 10.
Q: Will HIPS catch stuff that autosandbox (containment) misses?
A: No. If you are in proactive mode, then autosandbox will catch all files rated as unknown, and will allow all files rated as trusted. HIPS will do exactly the same thing, if you have it in safe mode.
Q: Will HIPS give me exploit protection?
A: No. That is in the "Advanced Settings" section, under "miscellaneous".
The first feature there, called "heuristic command line analysis," protects you against scripts and provides vulnerable application protection.
The second feature there, called "shellcode injections," protects you against memory exploits.
Q: So what in the world does HIPS do, then?
A: If you have enabled autosandbox (containment), then it is primarily useful for controlling the actions of processes that you don't want to block completely, but you also do not want to allow completely.
I will give you a practical example of how this can be useful.
If you will enable embedded code protection (this is inside the "heuristic command line analysis" section) for cmd.exe, this will increase your security, but on the other hand, it might interfere with the function of certain applications, which is why it is disabled by default. If you find that it interferes, you have another way to get full cmd.exe protection, if you use HIPS.
You can do like this: in autosandbox, you make an "allow" rule for the two cmd.exe files that are found on a 64 bit system. Then, in file list, you mark the two cmd.exe files as "unknown." (You might have to run them first, to make them appear in the list.)
Now you will get HIPS prompts every time cmd.exe runs, and you can make rules to allow your trusty apps.
Q: What else can HIPS do?
A: Let's take the following scenario. Comodo cloud lookup mistakenly whitelists a certain malware file. (Yes, this does happen from time to time.) The result is that autosandbox allows it, and so does HIPS -- at this point in the game.
However, this file is really just a dropper that downloads or spawns another file, the payload, which is the actively malicious part of the attack. The payload is rated as unknown.
Next time you reboot, the payload starts up early, before Comodo protection kicks in, so it gets past autosandbox.
But the payload is rated as unknown, so HIPS starts prompting you for every little action it takes, as soon as Comodo protection kicks in. (By the way, firewall will also prompt you for it, if firewall is in safe mode. And at CS settings, firewall will automatically block the payload from connecting to the internet.)
Q: What if I put Comodo HIPS in paranoid mode?
A: Then you will get prompts even for trusted processes, and you might go insane, because there will be so many prompts. But if you carefully read every prompt, you might catch suspicious processes that should not have been rated as trusted.
However, paranoid mode is not recommended for the average user, who will just end up by ignoring all the prompts. It is like the story of the little boy who cried "Wolf!".