Mil Spec BCG's from Colt, BCM & Daniel Defense brands are good. You can get those from Brownells.
Brownells brand BCG's are good also. They are much cheaper and will be fine for hunting.
There are many Gucci brand BCG's also.
Chrome is amazing. Mil-Spec was chrome way back when. Unfortunately the process was much more difficult in those times as the technology was not there in the 60's. It is now.
Young Manufacturing makes nice BCG's. As do many others.
Here is a link to a video that talks about a small portion of what is available out there.
F30
If you are on a budget, and want the best product/warranty for the price, buy a Brownells BCG in one of the many available finishes. Salt Bath Nitrade, Chrome or Phosphate. All will work to fine.
If you want top of the line, there is no best. Just tiers of quality that have slightly different features.
BCG's all need to be cleaned and lubed.