To know how good of a deal it is what is your states sales tax?
Also as stated above, what do you want vs need? Tough choice, I'm all about you live once so get what's going to make you happy so you don't regret it. Sure it may be more than you need, but if its truly what you want you won't need to do it again anytime soon. Off my soap box.
Truly the Eco will save you a large amount of money in fuel, I've had 3 CTD since 2003 and while I love them I get at best 14-16mpg overall. The Eco is going to smoke that #.
I have shopped since the 13's came out, local, east coast, west coast, Internet dealers etc, and it seems the line in the sand on a Base model Tradesman CTD Crew 4x4 Auto before TTL, is around 39K. Thats on a 14 2500, if incentives go up you may do a little better but that seems to be the line in the sand. My go number is $40 OTD, you can see I'm still driving my 06, LOL.
Sorry for the novel, good luck. Get what makes YOU happy.
Be safe fellas, have a good Father's Day!