But is he a grown-up Robin or Batman II?  It's just such a mess - the emblem seems to say "I'm Batman, No, wait - The 'R' means 'Robin' but the red circle means I'm neither!"  The cape is yellow - a carry-over from his Robin days, but why is everything from the chest down Batman?  Why the pointed mask and collar?  They scream "I want to add something original that was not a part of either original outfits, but try to, at the same time, evoke those identities but in a manner no sane individual ever would!"

This looks even worse than Bob Kane's red and black domino masked Bat-Man outfit which Bill Finger had to step in and fix.

In fairness, George Perez could draw any of the costumes in this thread and make them look good.

That's actually the second version of the Robin of Earth-Two's original adult costume. The version above, seen on the cover of JLA # 55 (Aug., 1967), was not seen inside a book until the next issue---# 56 (Sep., 1967).

Inside issue # 55, the no-longer-Boy Wonder debuts in a slightly different costume. There are no blue trunks, just grey leggings. Instead of the standard skin-tight super-hero shirt, he wears a grey jerkin with flared ends beneath his utility belt, similar to the red vest he wore as a boy. The bat-winged "R" chest emblem did not have the red circle. And his mask did not have the nose-piece. The effect is more of a balance between Batman's costume and the boyhood Robin outfit.

I have no direct knowledge why the costume was tinkered with for the first cover and the second half of that JLA/JSA team-up (and would remain the definitive version). In fact, most folks don't even realise the costume looked slightly different in JLA # 55.

I discussed the changes more at length in one of my Deck Log entries, linked here:

captaincomics.ning.com/forum/topics/deck-log-entry-181-mysteries-of-the-silver-age-part-one

Hope this helps.