I'm new here...first post actually. Just thought I'd chime in because I just went through the same thought process. I was considering a new/used Tahoe/Yukon vs a used Denali (Escalade's GMC equivalent) and ended up with a Certified Pre-owned 2009 Denali, fully loaded w/ 20" chrome wheels and NAV.
I've always been one to go for the top end model because they do hold their value better as time goes on and are generally more desirable. This makes it easier to get top dollar at trade-in time if kept clean or easier to sell if you want to sell it privately.
First of all, here are some facts about Certified Pre-owned. You will get a 12 month and 12,000 mile bumper to bumper warranty. This also makes it eligible to get a very affordable bumper to bumper extension. I extended mine to 5yrs (from in-service date) / 100,000 miles for $1200. Since my Denali has 31k miles and it's in-service date was Oct 2009, I basically have 3 yrs and 69k miles from now with bumper to bumper protection. Of course you could extend the warranty on the new Tahoe as well...
Look at it this way...The Escalade is a much nicer overall vehicle that will hold the value much better, you can get an equivalent or better warranty and you will have a higher trade in value the next time around. I've done the math a thousand times...you lose the most when you buy new. CPO's are the way to go financially. The biggest benefit is that you will get to drive a much nicer vehicle for the same upfront price price. The Escalade is just a much nicer vehicle than the Tahoe.
Hope this helps and good luck! Please make sure you post back here when you make your decision too!
JP (The New Guy)