I have not heard x7200 personally ,but have heard Anthem MRX 720 . Anthem are at different level (Both in price and sound quality) . U may need to decide based on the number of channels usage also .coz MRX720 has only 7 channels ,and can be extendable upto 11.2 using external power amps.Their Anthem Room correction(ARC) has top notch reviews.But I found difficult in their Graphical user display which is very good in Denon.
Anthem has a clean and refined power and the sound is neutral in my opinion.
Overall Denon will be all round performer and have good features for the price u r paying .In addition u dont require additional power amps in case if u r planning for only 9 channels.(extendable upto 11.2 using external power amps).U get additional feature of Auro3d decoder & Auromatic upmixer(paid upgrade) which is not available in Anthem. x7200 was the falgship for the past 2 years,so it should have good build quality too. Being a user of Denon ,the sound should be warm
How big is your room?
The power difference -Denon has 150 watts per channel (8 ohms) where as Anthem has 140 watts per channel ( 8 ohms) ,This should not make much big difference in db as per my opinion.
Best is to have an audition and decide.U may need to consider the best matching Speakers for both.
Good hunting.