All credit is due to the designer Dan Kennedy and his passion to create sonic nervana. The GR gear is as good as anything in the pro market being made today. And yes, the GR mic pre's are great on vocals as well as any other source you want to record.
I've talked to Dan Kennedy and Fletcher about the MP-2NV and ME-1NV. Part of it is Dan's genius. Part of it is Fletcher's arbitrariness such as getting Dan to go with the DI that put across the best sound with Fletcher's P bass.