From my experiences, you can't always really get a straightforward answer to this question.
The short answer - they rarely come up for sale which makes it difficult to gauge market value.
The long answer - I have posted numerous WTB's on multiple SW forums. I got a few bites, but the pricing was always all over the place.
I don't know about other foreign line figures, but I regard this as one of the figures that carries a triple risk.
Too many forcibly removed examples. Mismatched rockets (fake or forcibly removed), incorrect weapon, or fake figures (sanded down coo, replaced leg, etc).
Too many risks buying them from sources who may not have been sold a completely legit one, even though they claim to have a legit example. I've seen about 7 or 8 over the two years I spent looking, and from that, there were only two I could say were 100% legit. LuisG could chime in on this but I think he gave me a ratio of 1:9 or 1:10 for real vs faked/forcibly removed examples.
And the transit shipping risks - which I don't want to make appear as a slight to our friends living there - but I have heard too many issues with shipping items from/to Mexico to not consider this a concern.
Because of all this, authenticated examples fetch a strong premium whenever they turn up for sale.
No one wants to end-up being rooked on a figure in this value category, so getting one that's been authenticated with a COA is the safer, but more expensive route.