I have Comodo in one of my pc’s. I have D+ and Firewall component. I either disable AIS’s AutoSandbox or CIS’s. I run only one autosanbox. As for Avast Sandbox it’s not enabled because I have Sandboxie paid. Yes the D+ HIPS can be quite unfamiliar and hard to learn but it takes patience to see it’s value. I like it better than the Behavioral Shield of AIS.

Do not forget to set exclusions for Comodo folders(Program Files and Program Data) in the Avast Settings>Exclusions and in File System Shield>Expert Settings>Exclusions. Likewise place Avast folder in the D+ Trusted files and place all Avast processess in the Firewall>Define a New Trusted Application. I exclude Avast folders in the D+ Settings>Execution Control Settings. For starters I place the D+ Settings in Clean PC mode then after a week in Safe Mode. The firewall I have my own config for that.

You may want to save/export your configuration settings so if needed you can reload it. You can save more than one config settings. You can browse the user guide here

http://help.comodo.com/uploads/helpers/Comodo_Internet_Security_2011_ver.5.3_User_Guide.pdf

Drop by at the comodo forums also there are members there who use Avast and will help you with settings they use to make your experience with Avast/CIS a good experience. Both forums (avast/comodo) help out their members. Just ask and someone will assist you here or there.