Personally, I'd probably do an 18 Barbarian/1Fighter/1Cleric - that way you get tier 3 haste boost and divine might from cleric. You'd have an outstanding strength if you invest into your charisma. Thats a build I tinkered around with for a bit, but this fighter version still soars ahead in my opinion.
In terms of DPS, its hard to say. They're both very powerful damage dealing characters. I'd be lying if I gave you a clear cut answer because dealing damage became a much more dynamic process.
But, Damage wise, the build I outlined receives +2 Threat expansion from kensei, a constant +1 crit multiplier from earth stance on 19/20's, at least 3 Tiers of sneak attack damage dice, +6 to damage from kensei tree, and a spammable fist of iron which adds an additional +1 multiplier on ANY crit, +1 threat expansion, and +3 W damage.
Also, the ninja poison is surprisingly awesome. That ticks for 100+ (saw 140) every 3 seconds, effectively adding about 40 DPS.
Balance that against, say frenzy, which gives 3 Multiplier on 19/20, frenzy + death frenzy damage, and their strength bonus to damage + PA line.
I'm assuming they both have divine might, if I use the 18/1/1 barb build I outlined.
For all intents and purposes, I think its safe to say that their damage is comparable - its the other "stuff" that makes this build destroy the barb version - its the killer saves, which allows me to evade otherwise devastating EE otilukes from Ice elementals, which allow me to neglect the threat of a 73 DC flesh to stone from the end boss in EE what goes up.
Furthermore, this build has 25% incorporeal bonus + 17% dodge (28% while blitzed) + 333 per heal scroll due to healing amp access.
Also, remember that horc doesn't provide the extra feat that human does, nor does it provide stacking damage boost and access to action surge stats like human does. The strength discrepancy (also as a result of 2 lower charisma from horc if going with divine might) all needs to be weighed and calibrated to end up at an even number.
The barbarian cannot take advantage of manyshot without some serious feat sacrifice. You'd need to spend 6 feats to become proficient with bow damage = and a horc barbarian with 1 fighter level has 11 total feats. The remaining 5 are what? You need cleave, great cleave, overwhelming crit, power attack, IC: slashing. If you do that, then you lose stunning blow - a major tactic for which you should have plenty DC for if you combine barbarian strength with divine might. I wouldn't sacrifice stunning blow for ranged.
the 6 ranged feats: WF: ranged, bow strength, Rapid shot, PBS, manyshot, IC: Ranged.
I suppose you can lose IC: Ranged, and work stunning blow in - but meh, that depends on preference, I personally value stunning blow too much to deal with threatening enemies such as casters and assassins and such.
So, I've settled on Dance of flowers (cannot pass this up), Bane of undeath (need this for divine mights), and sense weakness (not even for the helpless damage, but because all the extra back end damage is nice against bosses), and play in LD 90% of the time.
I ended up dumping primal scream, and just calibrated my stats to be even with a rage spell - that way I only lose 2 effective str/con.
Hope that helps, the 18/1/1 is an effective build, but it'll get pwned a lot because of inadequate saves in EE stuff.
With this build, ESOS returns to being king DPS wise. Spamming fists of iron every 3 seconds gives a 12-20 crit range, with an extra multiplier on all 12-20 crits.
Also, it frees up my trinket to wear litany, which throws my cha even
So, with fists of iron 19/20's are x3 + 1 overwhelming + 1 devastating + 1 earth stance + 1 fists = x7 multiplier.
A frenzied barb is 1 ahead with a x8