Nymzavril wrote:

Why not buy the Xtar for a couple of bucks more?.....That's a genuine question by the way, as I'm in the market for a super tiny single cell emergency charger.

I have to assume that you are referring to the Xtar MC1 Mini Portable Single Slot Li-Ion Battery Charger, SKU 2396000, $7.41 (US) as that is the only Xtar model FT carries that is a single slot charger.
I never did a comparo before buying the Miller, so let's do that now.
First thing I see is that the Xtar is $2.25 more, but that's probably attributable to the better known brand name. Both units have a 65mm maximum battery length.
Ah, the Xtar's output:4.2V ±.05V/0.5A ± .05A.
The Millers output:5.1V/1.2 A.
That specification is new to version 9 I believe. I have the v8, and I'm fairly certain that it outputs 4.2V/1.2A. Not sure why the step up in voltage output.
They are both CC/CV chargers, both are reputable brands with a proven track record of quality and reliability.
The Miller ML-102 (this model) can be used as a portable power bank, the Xtar can not.
The Xtar can charge pretty much all sizes of Li battery up to and including 18650, while the Miller is a fixed size charger.
However, the Xtar accomplishes this with the use of a sliding negative contact mechanism. I personally have not had great experiences with that mechanism, but that was on a cheaper, no-name charger. But, a unit with no moving parts is going to be less susceptible to component failure than a unit with them.
So, I guess the decision hinges on just a few things: price, size flexibility vs. durability, and charge time/speed, as dictated by output.
I would still go for the Miller having done this comparison. I don't think I would bother with a multi-size charger unless it was a bigger, maybe 4-slot unit that could handle charging different size cells at the same time and it would have to be built quite robustly. I know such chargers are available, but I only use 18650's currently.(my 14500's, 14650's, and 18350's all expired over the last six months; most were real cheapies anyway.)
Well Nymz, this offer anything you didn't know already? Like, months ago? ~:-]