Over the years, PC/AC series has been polished to a high shine. GaW does not have this advantage. I actually find the interaction of inf/armor/arty/AA/AT/Air much more fun/challenging than in GaW. Also, while the names and maps are more historical in GaW, I have yet to find the game play feeling that much more historical. Admittedly, I have only played AGN so far and the MP experience is better. I like the fact you have to defend your objectives so some crafty human doesn't sneak behind and win the game in one blow.
GaW does have that "one more turn" feeling, but there is also a bit of that "grind" feeling in some scenarios. However, GaW has more varied and realistic "skills" that units receive based on experience. So far, GaW has frustrated me at times with units that do not progress (albeit, following history) or having units to deploy but not hexes to deploy them on.
And, to make matters worse for my budget, I see EUIV on sale for $32 The temptation is great.