Heralds: Tzeentch or Khorne?

Man, sometimes your game sucks.  Sometimes you're confident you're heading in the right direction only to have your opponent - that jerk - point out what you should have realized before rolling dice.

That you made a bad, bad decision.  Case in point; the good and the bad.

The Good: Herald of Tzeentch on Chariots with Bolt, Breath, and Gaze.  Man, I love this unit.  With a choice of two weapons per turn (Master of Sorcery) you can fly like a Jetbike to where you need to be... and the best place is behind a tank or a flame-template away from disembarked troops.  Bolt: Str8 AP1.  Gaze Str5 AP3 Assault 3.  Breath: template, 4+ kills, 4+ Glances.  Nice stuff!  The only question I have - and this isn't so much of a question as a longshot... can this unit move 6" in the assault phase, a la Eldar Jetbikes?  I don't think so, given that rule specifically says 'Eldar,' but does anyone have information I don't?  Regardless, with a Toughness 4, a 4+ Invulnerable Save, and 5 Wounds, this unit is a great disruptor.

The Bad: Herald of Khorne on a Chariot.  This option is 15 points vs 35 for a Jugger alone... but it's cheaper for a reason.  Okay, let's look at why I took it.  It's a Str6 Rending Furious Charge mini-MC.  It can crack tanks like nobody's business, even Land Raiders if he gets some luck.  He has a 3+/4+ save and 4 Wounds; what's not to like?  Well, he can't hide in units and he isn't fleet.  That means that Juggernaught is walking slow slow slow to get the Herald where he needs to be.  Meaning your opponent has no problem getting the hell out of dodge.

Okay, in last Saturday's tournament I took two of each unit.  Granted, I didn't finish the event but had to leave 1/2 way through, but it didn't take more than a few minutes into Game 1 to realize I made a bad decision including the Khorne Chariots.  I played Gauthic and his Mech Eldar, and he put on a shooting clinic for which I had a front row seat.  Fun!

I have that game on video, so I'll post it before too long.  It was a great game and I'm glad to see Gauthic is back with the army he loves best.  It's also the army I love best, so I had a bit of nostalgia watching him gun down my units.

Point is, 4x Heralds of Tzeentch on Chariot = Fun!  Any Herald of Khorne on Chariot = Fail!

Okay, it's not like others haven't pointed this out: Stelek's Daemons list, which I'm building towards, has Tzeentch Heralds for a reason.  Sometimes, I have to learn the hard way.

That said, there's a reason I test stuff for myself.  Sometimes you find options that work for you that others may not have considered.  Sub-optimal units are only that if you can't make them work.

Thoughts?