Both great guns
I have the 627-8 Performance Center 5". Handsome gun, very accurate with a nice trigger. Only gripe is that the standard round butt wood grip doesn't fit my hand well.
The Miculek has larger grips and has a removable comp/barrel weight.
Between the two, I'd take the non-comp'd model if you fire mostly moderate loads, single-action, and occassionally use the gun for carry or self-defense.
The Miculek model would be better for hot loads or if you do rapid-fire pistol competition. Keep in mind, however, that comps are verbotten in some types of competition, such as IDPA. Also, in some revolver-class competitions, you are limited to 6 rounds, so you have to underload the pistol and keep track of your rounds. Not a problem with the first 6 shots, but if you speed load with moon clips, you have to fuss a little to get round #1 to fire on the first pull (since you have two empties).
They both have similar accuracy and can be loaded with moon clips or without.