Probably the all around best gun refinisher is APW-Cogan, and their hard chrome is probably the best available.
http://www.apwcogan.com/
Here's other hard chrome suppliers that are known to do top of the line work.
Each has different pricing and options.
Final finish ranges from the original "orange peel" pearl-gray, to a brushed stainless steel look, to a full mirror finish.
At least one also offers plating inside the bore.
Most have brand names for their chrome plating, but it's all hard chrome.
http://armoloyfw.com/protect-your-firearm-with-armoloy-tdc/
Metaloy was owned by Bill Wilson at one time, possible still is.
http://www.originalmetaloy.com/
Tech Plate is big in the aerospace industry and offers about any finish there is.
http://www.techplate.com/firearms_pl.htm
Mahovsky does hard chrome cheaper then most anyone and has had a very good reputation in the past.
However, there's been a few questions about the quality in the last few years from some customers, and his communication sometimes isn't great, phone or email.
http://www.mahovskysmetalife.com/
First choice is Cogan. He has a better reputation then anyone.