I, too, think the 6.1 HEMI is very cool. I have a 71 cuda and am in the process of a HEMI swap myself. I considered a 6.1 and compared the cost to purchase and install the 6.1 vs. a 426 crate motor. I opted for the crate motor (actually a 472 HEMI).
According to my initial estimates, the overall cost for the crate motor was more, but there were so many unknowns and variables with the 6.1 install that I was afraid I might encounter some surprises and unexpected costs. I also received numerous amounts of feedback that led me to believe the crate motor route would make my car more desirable and valuable -- so I went with the 472, and I'm glad I did.