FreeMe: The new MK-IV's also have the ambidextrous safety, spring ejected magazines (for those of us troubled by numb and/or arthritic fingers), fiber optic (changeable colors) sights (in the Hunter model) and the trigger is AT LEAST as good as my older MK's if not better.
I will take some out and compare them when I get a chance.
Again (I have posted this before on a couple other threads here) the machining is just flat out amazing - I hope it carries through to the reaming and rifling of the barrel - I will check this with my friends Hawkeye Borescope soon as well.
AND... they just LOOK better to me.
Go look at one of these in a shop (in good light!) and disassemble it and look at the amazing machining "inside" the MK-IV.
You will be impressed.
Hold into the wind
VarmintGuy