oh you mean merchants that made textures for the tank wouldn't like GVU's.

but it wouldn't matter to the end user thou right ? 

but for texturing my Tanks n Mechs I'd advise allegorithmic ,quixel :)

Well merchants and end users - assuming we're talking the Poser community. We've found that not only merchants edit characters/textures/props/sets/etc. It was surprising to discover just how many Poser users get their hands dirty with the intricacies that are involved in creating content without the intent of distributing that. Which is why it's something that has to be thought about. Could you use GUV's for your texture output? Sure but you have to consider how useful it will be to the people you're providing the model to, should they feel compelled to edit it at all. That said, you're the one making it and you should do what feels right or is easiest for you. If there is one thing I've learned about this community - and perhaps the 3D community at large - you can't please everyone. You're more likely to please nobody before you please anybody and the odds of pleasing everybody is slim.