Company of Heroes is a great strategy game. It's not my favorite RTS, but I can very much understand why it appeals. At the end of the day, squad-based tactical combat is awesome, especially when you're in control from the top down.
I recently fired up Iron Harvest because the game's setting and re-imagining of history really appealed to me. Here's a bit of the description:
Iron Harvest is a real-time strategy game (RTS) set in the alternate reality of 1920+, just after the end of the Great War. The Game lets you control giant dieselpunk mechs, combining epic singleplayer and coop campaigns as well as skirmishes with intense action on the battlefield for multiplayer fans, Iron Harvest is the classic real-time strategy game fans have been waiting for.
Now, while I wouldn't say the game is as polished as CoH, there are many striking similarities. It's hard to see how this wouldn't appeal to CoH fans who want a slightly different setting than WW2. Try it out and see what you think!