I see the MX-780 getting on average about 4-5 months battery life as well (good alkaline batteries).
I have some customers, that are heavy users and I have the backlight & screen set to 20secs. They go thru batteries the most but still get a good 2 months out of theirs.
I have had a few customers that went an entire year on the included URC batteries. Got a call when they went dead "something is wrong with the remote". Once on site and checked it out "You have never replaced the batteries?" WTF!

The dealer cost on the MX-780 is cheaper than the MX-850 or MX-900. But the $299 retail price is kind of bogus, since URC allows the remote to be sold for $199 EVERYWHERE on the internet. I sell mine at $249 and 1/2 the time the customer will see it for $199 on the internet and balk at the price.
"For $249 if something goes wrong with the remote, I come out and swap it right then".
"If you buy it from the internet, good luck not watching TV for a week while waiting for a replacement"

I did have an idiot one time get mad with me, because I wouldn't swap his remote that he bought from the internet.
Customer: "You are a URC dealer right?"
Me: "Yes but I didn't sell you the remote"
Customer: "Well the car dealership has no problem with warranting my car I got from another place"
Me: "Well when people start paying $40K for a remote, I might get paid by the manufacture to care"