Defender (+def UV Med) vs. Bristling Buckler?

If I could I'd try for some kind of UV on the Buckler, too, though that seems unlikely.
With a Skolver Cap/Coat, which would be optimal? Would all three Medium boosts (assuming I upgrade the Buckler fully) combine into a Maximum boost, or would I be better off upgrading the Defender instead?
The defense on shields doesn't combine with armor, shields are a different line of defense.
And you still can get a UV on the buckler, just not much choice about -which- UV and you might have to upgrade more than one to get it...
I'm definitely thinking of upgrading my buckler for jelly palace and other piercing situations.

Then I am definitely sold on the Buckler. The defense comes out to about equal to the Aegis once they're both leveled up anyway, so, not a huge deal without the UV. I'll make much better use of the damage bonus than the shield defense (since once my shield is popped I'm running as fast as my robot feets will carry me). Though sadly, yeah, it's gonna take aaages to find a UV on the Buckler I really like. But that's okay because it's awesome.
Thanks for that tidbit! c:
I ended up going with the Buckler. I have it upgraded to a Targe already and I am enjoying the look quite a bit. The added damage is quite nice.