Leonardo (Lago?) Maddog 2008 (FSX user)

Does anyone have this plane and what is your experience with it? I know it is high fidelity, so that isn't in question, but I have also heard it is about as hard as you can get on framerates. Is it worse or better on frames than the PMDG 747? (that is about as tough as my system will handle at my preferred detail settings) Is it so much more of a pleasure to fly than the Coolsky Md-80 that it is worth it somehow?