I happen to have a few of each. I use them alternately for clays and birds. Therefore I can talk with direct and reasonably substantial experience.
I won't bother going over the differences in specifications (screw in chokes in 20 ga. vs. not, etc.) but I'll focus on the "other" items.
RBL
- great value
- tough as nails
- reasonable, but not great fit and finish
- generally muddy and unattractive case coloring
- so so engraving
- good dynamics in the 20 and 28ga., poor dynamics in the 12 and 16Ga.
- future appreciation very uncertain. Not a "classic" more of a workhorse

Parker Reproduction
- excellent fit and finish
- attractive case coloring - but thin, Cover with shellac and no problems.
- so far. no problems at all with single triggers, double triggers, or anything else. That includes many rounds of Skeet and Sporting Clays as well as Hunting.
- good dynamics in 20,28 and 12 ga.
- it is a modern day classic as reflected in its appreciation.

In the end, based on my direct experience, I believe that the RBL is a really good gun, but that the Reproductions are superior. That value difference seems to be reflected in their relative prices.