Quote Originally Posted by mega_tonberry
...I use the celestial ones cuz I went though to much friggin trouble to get them.
Seconded.

BTW, I think that the celestial weapons are tied into HP or MP levels for their owners so if tidus is dying(we should be so lucky, lol), his celestial weapon does much less than if he was at full. this is both a blessing and a curse as characters like Auron are more powerful when they're dying, but less powerful when they're at full HP. I dont have the specifics, but its awkward anyway, and suggests that customised weapons are better and all celestial weapons are good for is boosting the aeons...

In my current save, I'm going to try for both anyway (probably add another 50+ hours when I get started...)