Thank you guys!
Far-seeker, "homemade pcbs" are pcbs I need to made by my own hands - trace, print, solder etc. Since college I hate it 
I want to isolate controller and heater circuits, so mosfet is not acceptable (DVDdoug, thank you for note about AC, I never had known it).
dc42, as a hardware user, I don't like to enter menus just to adjust speaker volume or something. And same about buttons - dials are more informative and quick to set. Apart of my preferences, system with "old style" controls will be elder friendly.
What are you thinking about my last idea to make controller of two CPU modules - arduino mega and something like raspberry pi? First will work in realtime, while raspberry will be used as user interface with way to control over LAN via web-interface?