Mike - neither carb should plug with debris if your filters are working.
Having said that, will attempt an answer to your question. It actually depends on your use/expectations of the truck. If it is a numbers matching vehicle for shows, then the Holley 847 is superior to the Carter BBR.
If it is a truck you use, I wouldn't use either of them!
Beginning in 1933 Carter always had a "price leader" single barrel. From 1933 to the early 1950's, it was the BBR. Of all of the carburetors Carter ever built, the BBR was the ONLY one Carter felt needed a troubleshooting chart!
http://www.thecarburetorshop.com/Service_Carter_BB_downdraft_issues.pdfIn 1949, Carter offered three grades of single barrel carburetors: cheap (BBR), mid-range quality and cost (W-1), and best (WA-1). Carter released a universal WA-1, part number 413s as a replacement for the 1949 KB BBR-1.
If I were to issue a numeric "quality" from 1 (awful) to 10 (wonderful), the 1949 version of the BBR would be a 5.5 (D-), the Holley 847 would be a 7 (C), and the WA-1 would be a 9 (A). Carter felt the same way about the BBR. There is a long, funny story about the 1947 Plymouth BBR-1; if you want to hear the story, give me a call. You might find it online, as I have typed it on a number of forums.
Original applications of the WA-1 (different part numbers) included Pontiac, Oldmobile, and Packard.
EDIT: and in the FWIW category: the Ford model A Zenith detests dirt; but if you maintain clean fuel, it will certainly outperform the Tillotson. I personally do not judge a carburetor by how it handles dirt (unless it is military). The biggest issue with the Ford model A Zenith is the cross-passage feeding the comp jet. On a vehicle that sits for a few years, it will probably become clogged with dirt/rust. In any event, any time a Ford A Zenith is rebuilt, the access plug to this passage SHOULD be removed, and the passage rodded out. Failure of a mechanic/rebuilder to do this simple procedure will cause the carb not to function as designed. On a driven vehicle, should not be an issue (if the fuel is clean).
Jon.