No it´s such a beautyful and visual high quality plane.
The only thing that is disgusting is the position of the left pilot footrest bolts. Every time I look down I see this:
The screw is half-way clipping through the cockpit sidepanel, that´s a no-no for the perfectionists among us 
But don´t worry I am going to take care of that in the PMDG forums and have a nice talk with the developers. I know they want to see this ugly glitch fixed too. To be proud of being able to say: We developed the PERFECT virtual Boeing 737 fleet!
They have fixed a slight gap between a cockpit element and the cockpit wall behind the pilot´s seat in the DC-6 Cloudmaster too I was ticketing to PMDG, I am sure they are happy to fix the position of these two bolts too 
The differences are not that obvious but catered for the true 737 fans.
I have already noticed some differences compared to the -700 series.
Here we have some nice announciator lights that show eh… sorry I don´t know what purpose they have because there are no tutorial videos of the 737-800 freighter yet:
The next fan service is getting not one but TWO cargo plane variants
One is the original Boeing cargo plane, the other one is a converted freighter version.
Sorry I don´t know the exact technical differences between an original freighter and a modified converted freighter (I guess in the converted freighter the cargo door is cut into the hull, the windows are still there but blocked, and some other details in the cockpit and the cargo room, but I need to read about this on Wikipedia.)
The BBJ business version has more fuel tanks to select (to equip the plane with) and some other details.
The 737-800 is the BEST 737 package so far! Absolutely recommended. The only sad thing is that the circuit breakers are not functional.
Look at this lovely plane:
The circuit breaker panels can be illuminated.
All of these flashlights mounted in the cockpit can be switched on and oriented to a specific spot in the cockpit freely.
But this was already shown in many showcasing videos. A wonderful plane.
Too bad that this website is down because I wanted to plan a flight vom Hamburg to Köln right NOW!