Basically, it's a matter of personal choice and comfort. For example Dustergirls' 340 is a "GIANTKILLER" with the Holley, which is great for her combo. Mr. Yuck prefers the "six gun" for his 440, which is a very LETHAL combo! However, the Street HEMIS and Max-Wedges ran great with Carter AFB"s and were extremely tunable. The fact is, yes Holleys' are a bit more "user-friendly" when it comes to tuning than Carters since there are more of them in circulation and the racing industry has had MORE development time with them (Holleys). Carter AFB's can and will run as good as a Holley, IF, they are tuned CORRECTLY for the individual motor combination you have. They are more sensitive to compression, cam and ignition timing, since their secondaries work off of engine vacuum/airflow! AVS's and TQ's are more forgiving, with different engine combinations, mainly due to the spring loaded "air door" secondaries. For most street and street/strip motors Carters can handle most applications (again, TUNED CORRECTLY), but Holley continues to be the standard in street/strip and "all out" racing!