Well the main reason is from CT said about it multiple times, WPC contains some beneficial things that WPI does not and he recommended it over WPI. But I doubt it really makes a major difference. It is also cheaper.
WPI does taste better, and mixes better though.
Where are you ordering from anyway? Proteindirect?
I’ve been ordering from myopure.com.au - I just had a look at Protein Direct and it looks like they might be just slightly cheaper on some products, so might have to give that a go.
I’ll go read up on what CT had to say too, sounds interesting.
The vitargo seems quite popular. I’m not sure how I managed to have not even heard of it before.