Usually, but there are times when I have a glut of miles and not as much cash sitting around. In that case, I'd rather get the 1.4 cents per rather than have to come up with $700.

Really, you have to figure out what it's worth to you. I redeemed 50K for an unrestricted coach a few months ago for a ticket that was last minute, but could be purchased for ~$500, so that's about 1 cent per mile. At the time I had 300K miles in my account, and I'd rather spend out of that instead of paying the cash, and an unrestricted award was eligible for upgrades rather than being stuck in coach the whole trip on a 25K award (that wouldn't work anyway for the non-Saturday schedule I wanted).

Figure out what works for you, and go with that. I'm sticking with around 1 cent each for an airline mile, but even that's flexible depending if I might need an unrestricted ticket for changes, or something else I can't get from the purchased ticket. I know people always want to get the best value (and I do that a lot), but I also want to make sure I can do what I want, when I want even if that isn't the theoretical optimal use. Be happy.