Once more we see the primary attack upgrade being the route of choice.  It was very clear cut with Dino-Rang and Prism Break, while Bash's upgrade were a bit closer.

Interestingly enough, Terrafin, much like Ghost Roaster, came through with Sandhog being preferred over Brawler.  This of course speeds up his burrowing and allows him to damage enemies while burrowing.  I think this is another case where the secondary attack really improves the character.  His punches are already powerful enough, imo anyway, and letting him turn the burrow into a quick safe-haven where he can lauch mini-sharks and cut up enemies with his dorsal fin is awesome.  I think it really sets him apart.  It is very much defensive, but with the speed and attack as an added bonus.