I don't have a huge collection of NECA TMNT anymore but the one that stands out in my collection, and almost certainly in part just for preference reasons, is Samurai Mikey. Besides not having the correct wrist articulation (come the fuck on, NECA), that is a solid-looking and solid-moving figure with so many great accessories.
I missed out on getting the Scumbag two-pack when it was reasonably priced and available from a Canadian seller. I regret that, because I think Scumbug might be one of the figures I keep going back to, that I don't have, as possibly being one of the best in the line.