Both are excellent games but vary greatly in complexity. I own both and have had far more play with M44 largely because it is easier to find opponents and it has quicker play which fits well into my schedule.
I second that^
As far as replay value, one can get tired of those base M44 scenarios pretty quickly
But not this^ because We've(I play with my family) played those base scenarios countless times and haven't get enough yet(really).
The wonderfulness about M44 is that you can try different strategies each time and after several sessions the game keeps being "juicy" enough to provide fun, excitement and laughs. It really is one of our favorite board games ever!
And, we own other expansions that we haven't tried yet(like the Eastern Front and Mediterranean Theater) So for us, this game will last for years to come and totally worths every penny.