post-processing - week 2

i had noticed after i reduced the resolution on the week 1 photos that it made it hard to see the difference in the before and after
and thanks for the comments confirming it's not just my eyes either
so i took a different approach for week 2

for week two we learned how to turn a picture black and white
and how to do layers
and how to add back color to your black and white photo

here are the before and afters i made...

i really enjoyed this technique
which do you prefer?
what would you change in them?