I *ahem* USED to watch the Mexican dub, because it stopped showing after Advance Challenge (but they did dub Chronicles).
I love the Mexican James, with all the Mexican related jokes and stuff. For example the TR motto is different every time, with "stars" being changed for a Mexican place:
~ English line - To extend our reach to the stars above
~ Original Mexican line - Y extender nuestro reino hasta las estrellas
- And after a while they started to change "estrellas" to things like "Apatzingán" and "La vecindad del chavo" (from an old, popular Mexican series)
The only thing is that the rest of Latin America (who also gets this same version of the dub) might not get some of the jokes.
And continuity... UH. Since here in Latin America we only get the US version of the Pokemon games (we don't get them translated), the moves don't have "official names" in Spanish (I understand they do in Spain, but they're two different dubs), so they make them all up. That's not an issue really, the issue is that they sometimes forget their own attack names. Razor Leaf used to be "Hojas Navajas", and when Grovyle first appeared in that watermelon episode, Leaf Blade got the name "Hoja Sable". Well, when Ash's Treecko evolved, we got a Leaf Blade named "Hojas Navajas", screwing up both the original Leaf Blade name and the name for Razor Leaf.
But it doesn't matter now. We don't get the Mexican dub anymore.