Quote Originally Posted by wyldstrykr View Post
i dont have a max su (4/5 i think and its the base class)
but selling those gives 3 rainbow crystal and a 5000 gold

not sure what is more valuable.....
Selling event units for Rainbow Crystals isn't usually the best option as you will need to sell a lot of them to event think about getting a decent amount of crystals. That is pretty much the last option you should look at if you plan on playing aigis for a long time or only need a few more RC's to reach a certain unit in the Trading Post.

Depending on the unit you can hold onto them as they may share the same skill as another unit in your team or future/past event unit you may want to use in getting there skill lvl up. (For example some collected Emilia during her event to use to Skill up Maribel upon her revival event)

Or use them as Lolix said as a mini plat armors worth of xp when combined with 3 spirits of your units rarity. All in all we can tell you what the better choices are but in the end it is your choice, you may feel those 3 RC and 5000 gold is the best way to go but remember you can always get more gold in Mondays dailies and if your a free player who wont get a lot of chances to sell gold or plat units for RC's it will take a lot of event units being sold to get a decent amount of Rainbow Crystals.