Mendosa

good questions!! Hopefully I can help you out with some food for thought...

I would say to you to go with the edge loop method. The crease tool is good but right now its one of those things that a few companies are trying to implement into a production pipeline , this is in order to cut down on having to use edge loops. The issue with creasing is that the history of the crease isnt kept if you have to get an obj of the object or model in question, it gets dropped on export.

So in this instant its fair to say stick with the edge loop method. Practice how you loop because you can learn how to minimise loops. For example you may only want to 'sharpen up one or two edges but the loop will go around the model when its not needed in other areas, so learn how to terminate edges, ie: kiting. when the edges create a kite shape and you delete the unwanted edge in the middle. These are ideal for hardsurface as its not necessarily a deforming surface per say.

The Iron man model is clearly a very clean and well modelled mesh, Its loops are there and have been utilised very well. Its always good to keep you meshes as light as possible and add detail where you need it. But at the same time keeping everything optimised across the board for good uvs and textures and also to look good in the renders with having a lo res look (if thats whats needed)

Alot of the time , especially these days, Zbrush is used for concepting so the meshes are going to be super high and arent going to be at all useable for much. Alot of the time we do remesh but now with the model toolkit in maya its easier than using the remesher in zbrush because the result is dictated by you and not an algorythm that may give you some weirdness in your mesh. So dont rely on remeshing alone. It has good and bad points. By all means use it to maybe get a cleaner mesh, but be aware it wont be spot on, it wont give you a perfect, production ready mesh out of the box, it will get you a certain way, but chances are you will still need to go in and give it a tickle.

I hope this helps you out a little. If you have any more queries please feel free to ask

cheers
Jay