The 3.73 vs 4.10 really ends up being personal preference unless you intend to exceed the GCWR of the 3.73(21500).
The 4.10 gets you up to 24000.
Next, if you haven't towed with either, then considering the 1500 bunch tow this much...it will be much more pleasant than that.
If you are going to be climbing steep grades everytime you tow, get the 4.10.
If you have no hills, 3.73 will be just as good.
If the camping is just a few times a year, again 3.73...if you tow as often as you just drive around...get the 4.10.
The new 8 speed is to make the 6.4l really wake up...so 3.73 will be an even better match.
Once again it is personal preference if you are under 21500 GCWR...the 4.10 isnt going to make the truck world's different and the 3.73 really isnt going to get you any better or worse mileage.
I said I would not be getting the 3.73...but I did on my newest addition...it had what I wanted and at a great price...so I compromised...haven't had any issues with that decision.
But if you are buying new, and even though the discounts seem great...get the 8speed and enjoy not having to wonder what could have been.
Good luck.