cleaver spin is at least a -20 on block ...
the bf3 (the walk and grab) has armor but you have to get in within it's range otherwise you miss and whiff punish on it is too easy, also ducking opponents can escape it. so if Deathstroke is shooting low machine gun bullets then Grundy takes the hits and whiffs the grab - worse case scenario
I've played Grundy for 9 hours straight over two days, on the latest build (pre-release copy with full roster) and if any of you guys want more info I can pm you because there are certain things that some wouldn't want them to be spoiled.