+damage on shield

Tetra nailed most of it.

A shield being

Eth. does nothing for your

Smite damage (or any damage), it only buffs the defense of said shield. So in terms of dmg output, it doesn't matter one bit.

The comparison of Exile vs HoZ as dmg choices is a flawed one though imo.

HoZ is kind of a cheap (after week 1 that is) entry all-rounder for pally shields (a pretty darn good one mind you). Though personally, I would never bother with an

Eth. one. Blow a socket on a

Zod for nothing but a bit of unnecessary extra def? No thanks.

Exile is the ultimate defensive choice (which is why the dmg comparison isn't the best one imo). Between

Life Tap, sanc and the fact that it can be

Eth and self-repair, the overall defensive capabilities it adds to a pally are frankly a bit ridiculous for a single item. Even more so with 45 res (if you need that).
It does offer some additional offensive bonus for a smiter though in that having

Life Tap on your shield opens up your gloves and lets you use

Steelrend or the like for extra ed/cb instead of drac's.

Either way, if you're looking for the ideal offensive shield and max dmg output..you're not looking for HoZ. You're also not looking for Exile. You're looking for Phoenix.

Ultimately, as so often, it boils down to playstyle, preference and the rest of your gear.

And lastly, a

Sacred Targe isn't necessarily the best choice for your base.

Sacred Targe = highest block

Vortex Shield = highest def

Zakarum Shield = most stable dmg

Sacred Rondache = teeny tiny bit of extra dmg

Merely Kurast isn't the best at anything and kind of a waste in general (in my personal opinion).

Depending on your build and the remainder of your gear, you're forced into a fair bit of dex anyways (e.g.

Phase Blade reqs). Couple that with a high enough lvl of

Holy Shield and you don't need a sacred target for more block as you're quite possibly base-capped anyways, even with a lower base block on your shield.

Side note:
If you do choose to go for an Exile or Phoenix with ed instead of res, even perfect ed bases tend to be quite cheap as most people opt for res instead. I hence wouldn't waste the rw runes in a non-perfect base.