I see this huge thread about hardware. Odd that nobody discusses the elephant in the room (that the MH X10 processing is terribly flawed.) And has nobody figured out why the house-code-only (eg XA, XB, etc.) commands are set up wrong? Does nobody else understand that you can send ON and OFF to all addressed units? Or that the ALL LIGHTS ON | ALL OFF | ALL LIGHTS OFF stuff doesn't set states properly as of some time last fall. That is the least of the worries though (the primary problem is inside the seven-year-old process_serial_data function.) See the "X10 Idiocy" post for more details...
Anyway, the CM15a for sure. What else can download timers and macros that control everything in the X10 universe (including alarms, camera bases, etc.) Clue: downloaded macros in an HA setup are like stored procedures in databases (invaluable.) Does that clear the fog at all? If you can do it without the PC, do it without the PC. It doesn't seem to hard to understand that EPROM is more reliable than a clattering PC and looping PERL code! You use software to build on top of the scenes, macros and timers. Get it? Then you can go on vacation and not have to worry about your computers.
Of course MH doesn't support it. Sure as hell not on Windows and not very competently on Linux either. And that is pathetic because I posted the Windows treatment months ago. In the three months that I used MH with the CM15a, I never had one lockup or missed signal (in contrast, the CM11a's signals would collide and disappear at random, usually due to motion sensors.)