I have my eyes on a used , Desert Eagle MK VII in 44 mag
Anything to look for ? Exterior condtion appears to be in very good shape , everything seems to work fine ??

I have been wanting one for awhile now ...this might be my chance

Are the .44 MK VII models pretty much able to shoot any 44 mag ( I know you should only use the jacketed bullets only )

Trigger on this model seems better than the newer model I rented at a range ? Is there anything special with this version ?

Besides being made by IMI/IWI. They are built like tanks. For some strange reason I think they were made a bit better than the mark 19s. I rarely had issues with my mark 7.

As noted - jacketed only.  Lead bullets, or even bullets with an exposed lead base have reportedly clogged the gas tube.  

You also need "full power" ammo to get the gun to cycle consistently.  The MK-VII has a lighter slide, so it is a little more tolerant of less-than-full-power ammo, so you should be a little more flexible there.  My MK-XIX runs fine on 240 gr. American Eagle or Win White Box ammo.  I haven't tried it with anything with a lighter bullet weight.

I wore out the extractor spring on mine. Upgraded to the polymer one and my extraction issues went away. Sold the pistol off several years ago.