I restarted my Colosseum game, and I'll use my 2 first flutes on Suicune and Raikou, as I'll try to get the right natures and IVs. The last one will probably be Oh-Ho or something else that worth it near the end... ;)
Hum... you're rigt about Oh-Ho... Didn't even think about it before posting :P My bad ;)
Anyway, my last one would be something strong in the end...
...Because it is a Poke that takes rather long compared to most of the others to purify, that's why. Also - depends on the nature of the Poke - some natures led to faster purification using a certain method and all, so that too can be considered. Also for those which you happen to want to be UT.Look, why is everyone saying Metagross? When it uses Shadow rush it is really cool but it is actually quite easy to purify. I purfied it on Mt Battle and it took lvl 7&8. Patience is the answer. Just DON'T use one on Metagross.