Edage Katsura is the better artist in my opinion. CTR art trumps V16, and RSR trumps GTB.
Unfortunately he's done so little outside of VIPER that its hard to compare his other work against TKs (which by volume alone is clearly superior.) The one thing I know he's got his name on was a one-shot anime called Hi-Me-Go-To, which I didn't find all that impressive compared to CTR/RSR.