How does the nickel finish hold up compared to the blue? Is the nickel harder to maintain? Thanks, makilly

I wouldn't say it's harder to maintain, you just have to clean them a little differently.
For one thing, no Hoppe's #9 on nickel.

And the polishing compound Flitz or Mothers seem to do a first rate job for a shine.

I have a nickel (pre) Mod 10 that's 67 years old and it still looks good!