If you want some objective information comparing verticals check out:HF Vertical performance and test methods and results
available through Champion Radio Products.
Written by Ward Silver N0AX and Steve Morris K7LXC. They compared quite a number of verticals (6BTV, Butternut, R8, CP6, Gap Titan and others) against full quarter wave reference vertical antennas over a 64 radial ground screen. (They have a picture of the helium balloon lifting the 80 meter wire thats kind of cool). They carefully detail their test methods which is something I found very educational. I believe the book answers your very questions and understanding test methods will help anyone in discerning the available data.
I love discussing antennas with other ops, because there's nothing like talking to someone who owns a particular model to find out details about how they hold up in actual use, what parts fall off first
and how the customer service was. But the comment "if I can hear them I can work them" that you often hear probably doesn't really answer your questions.
A generic comment: If you are looking for an antenna that "does well" on 80-10, the Butternut 6 band and Hustler 6BTV tended to lead the pack because the other antennas either didn't have 80 meters (R-8) or were well behind these two in measured gain. (IIRC the Titans 80 meter gain against reference was something like -19 dB, way behind all the others) Remember that these two were tested over a pretty decent radial system. If you are looking for something that covers 40-10 the R8 fared well on most bands but that was a "tighter" race in terms of gain measured. You should seriously think about what bands you wish to cover, how much money you wish to spend, how much room you have, then look at the data to see what fits.
Good luck 73 de WB0FDJ Doc