One thing I did find which annoyed me is an advert for vegan bodybuilding powder that said "Vegan diets are typically low in protein".. Says who?
To be fair most vegans I know have shockingly low levels of protein in their diets. Not helped by the fact that some pro-vegan literature you'll see seeks to make a virtue of this fact.
Regarding Bulkpowders, their customer service is terrible. Last few times I ordered it took ages to arrive & it's very difficult to get hold of them (they don't publish their phone number anywhere so I had to get hold of it on the grapevine). If you want decent cheap supplements & good service your best bet is http://www.ironscience.co.uk/
multiple MDs and PhDs I have met and seen in conference advocate for lower protein, around 10-15% of your daily caloric intake. However, that is all types of protein, meat included. They say they do not see ill effects of higher plant protein, when eaten as whole foods. of couse to gain you will need more protein.