I prefer Searren over Forren. My reasoning could be as simple as, "PSIII came before PSIV and had Wren first." PSIV simply borrowed the idea and fleshed it out, as it did with several other characters.

That, and who wouldn't want a comrade who could blast enemies one minute with a [insert type here]Shot and transform into a vehicle the next? ;p PSIII Wren is much more useful for this reason and essential to the quest, while PSIV Wren just gets interesting toys in battle (the optional units you go out of your way to find).
But then, it all depends on preference now doesn't it?
