Hello Ed, useful question.
1. Yes,it is interesting to find where things are made.Much of the time,we all tend to assume that the various ESC brands might each bemade in different factories. With a bit of simple research we can see that there are only 4 or 5 major manufacturers of ESC's in the world.And thatfor each of the brand lists given above, they are actually all made in the same factory -and leads to the almost certain conclusion that they are all the same devices. Much of the time, theyaresimply re-badged by retailers with a different colour sticker and new name. However, some retailers do not bother to re-badge them at all, and simply sell themwith the original "ZTW" or "HobbyWing" etc, factory nameon the label. In my opinion, this is a verymuch preferable situation.At least we all know then,exactly what ESCwe are getting ...

2.The fact that most of the ESC'sweall use,are made in just 4 or5(chinese) factories, has actually been common knowledge for some time.
See: http://www.rcgroups.com/forums/showthread.php?t=1333719
http://www.flyinggiants.com/forums/s...ad.php?t=64216 -the forum name that was auto-deleted is: "Flying "Gigantic" things" -FG
http://www.rcgroups.com/forums/showt...627&page=3

-However, at least the brand lists given above,providesome sort of comprehensive reference guide,for most of the ESC's on the market at the moment.

3. You ask: <span style="font-size: small">How can we be certain that the list of brands given above, are each made in the same factory ...?
</span>It is not difficult. In most cases, it is simply because the branded program card or program box,used forprogramming different ESC parameters, is identical between the various brands made in the same original factory.This is by far the biggest give-awaythat these different brands are identical, thatthey must come from the same factory,and that they areinter-changeable with each other.
The program cards used for ZTW vs. HobbyWing vs Sunrise Model ESC's (for instance) are different and distinctive, and when one branded ESC uses a particular generic program card, then we can be 100% certain about the original factory in which this ESC must have been made.
4. In a few cases,we can rely on the appearance of the ESC and on its specifications (weight, size, electrical specs, number / sizecapacitors etc ). Especially for 100AESC's and larger, the appearance of a ZTW-derivedESC is quite different from e.g.a XingQiong (XQ)-derived ESC, and then we can easily identify the original factory in which it must have been made.

5. It has been discussed before, about the possibility that a single original factory might make severaloutwardlyvery similarproducts (i.e. ESC's), withdifferentquality levels and specs.The fact is, most people find that this is absolutely not believable,and notpossible.It is just not the way chinese factories work.Both myself and many other people have dealt over severalyears with these ESCfactories. If we wish to order 1,000 or 10,000 ESC's from HobbyWing, in different current ratings, then HobbyWing have their standard ESC models, and we have to simply order the standard products. There is no room for negotiation on the specs. They have their rolling production lines,manufacturing their standard ESCproducts, and that is what we all get. There is certainly no difference in programming between the different brand ESC's which are made in the same original factory.
In addition, we all know from experiencethat whether we have a Hacker SB-Pro series, Hyperion Titan, Airboss, orOK Hobby Infinite, then the 40A ESC model of each is identical between these different brands, and they have all the same features and functions (and also identical appearance beneath the label). There is no difference at all between them.

6. Finally, Ed, please note this is not a pointless or academic argument.
The simpletruth is,that the price we pay for each ESC, even when they are made in the same factory and are identical, varies massively depending on the particular name placed on the re-branding label. Let us take some examples,for a 70A ESC:
a. Hacker X70 SB Pro Brushless ESC -costs $109.99 - http://www.aero-model.com/Hacker-Bru...B-Pro-ESC.aspx
b. ZTW 70A Brushless ESC w/ 4A SBEC -costs $44.99 - http://www.altitudehobbies.com/ztw-7...-esc-w-4a-sbec
c. HobbyKing 70A ESC 4A UBEC -costs $29.99 - http://www.hobbyking.com/hobbyking/s...C_4A_UBEC.html
d.TURNIGY TRUST 70A SBEC Brushless ESC -costs $28.73 - http://www.hobbyking.com/hobbyking/s...ontroller.html

e. All these4 ESC's are manufactured by the ZTW factory, they are all rated at 70A (continuous), they all take 2S-6S Li-Po, they all have S-BEC (3A to 4A), they are all similar sizes and weights (size and weight will depend on length of heatshrink, length / diameterof wires etc).
They all come from the same production line in the ZTW factory, and all reports show (see below) that they have almost identical circuit boards, and use identical components.

<span style="font-size: small">And yet we can pay between $28.73 and $109.99 (almost a 4-fold difference)
-for what appears (basically) to be the sameESC device ...
I wonder: Is the $109.99ESC, really 4 times better than the cheaper one ...?</span>