HO1 - I had some fun with it
HO2 - It tries to put in everything including the kitchen sink. I find it very easy to get lost in details and keep yourself from "grand strategy". Too easy to create loopholes (aka: American Army consists of paratroopers and tank divisions only). Eventually feels to me like playing a spreadsheet vs playing a game.
I have been gaming for 30 years now (I am 39, and I am a gaming whore), the most fun I have had was playing World in Flames, version 1.0. It was simple, clean, and yes, had some quirks, but fun nonetheless. WiF, the Final Version, gets to be very much like book keeping and micromanagement.
SC2, playing against another human is the closest I have found to playing the original WiF. The rules are clean, the map is great, and you have enough time as Axis to be bad before the U.S. of A. enters the war. Either by way of the developers, or by some fantastic modders the AI will improve for solo play. SC2 (and SC1 for that matter) capture the feel of what a strategic level game should be.
Nuff said