1) It hasn't been released yet. No one should use software that hasn't been released yet. (It has something to do with the space-time continuum; I'm still waiting to hear from Jason Lisle on that one.)
2) The number of a man is 6 (Revelation 13:18), which is 9 upside down, and the number of tribes is 12, and Paul wrote 3 letters to the Corinthians but we only have 2, and the number of God is 7, and the number of my dentist is 402-371-1170 (she's very good, actually). If you add and multiply and subtract and square all these numbers in a really creative way (I'm not a mathematician, which helps) you'll get 2020, and isn't 2020 bad enough already? Not to mention the fact that 9 is 6 upside down, and Australia deserves much more than Logos 6, don't you think?
3) I'm still working on reason number 3, but it's a doozy.
4) Do you use Logos 8 to its fullest extent? Really? Tell the truth. God knows if you're lying. I bet you don't know how to type in a really complex search, like "Show me every time Jesus talked to Peter about John but it was nighttime and Peter was washing his socks, in the imperative mood and optative voice, WITHIN2WORDS".
5) Logos 8 is just a baby! It's barely two years old! Would you trade in your youngest child to get a new one? Of course not! Well, Logos 8 is like Bob Pritchett's two-year-old. Are you just going to kick that blubbering toddler down the basement steps to live with the bats, with nothing but a Zune that only plays "The Happy Minstrels Worship Team Plays Bebo Norman's Greatest Hits"? No, you're not. You're a good person, and you're a nice person, and you're glad that the Savior doesn't just kick us out when a new model comes along.
* None of which will apply when Logos 9 is actually released.