Thank you for your reply. It is very helpful. Would you be so kind to explain why is the Scar-veteran better for me than the Oldblood? I have no Sauruses the Scar-Veteran could boost.
Absolutely, I would be happy to expand on my preferences.
In terms of the Command abilities the Oldblood has the better self use. The ScV's Command Ability is obviously intended to be used on a large unit of Saurus in order to gain the maximum benefit. However, it is still effective when used by the ScV on itself due to the volume of attacks on this model.
That brings us to the next point of comparison. The ScV has significantly more attacks than the Oldblood. It has double the number of weapon attacks on two of its loadouts. The spear is the best of the three choices in addition to its Fearsome Jaws and Stardrake Shield attack. That same shield gives the added benefit of allowing the model to ignore -1 rend. The Sunbolt gauntlet can be strong vs Chaos Demons, but is generally not going to contribute as much to the game as the -1 rend mitigation.
The Oldblood is a better target for a Skink Starpriest's Serpent staff ability. Which is not to say the ScV isn't still an excellent target as well.
These next two differences are what sets the ScV apart in my opinion. It's Jaws hit on a 3+ instead of a 4+. The trade off for its better hit rating is the Carnosaur's Massive Jaws only do D3 vs flat 3 damage. This means the ScV trades some effectiveness vs monsters in order to be much more effective against non-monster targets.
Now, to get back to the volume of attacks on their primary weapons. The ScV's Spear is an ideal target for equipping the Sword of Judgement. If you are unfamiliar with this particular artifact it cause the ScV's melee weapon (spear) to deal D6 mortal wounds to monster and heroes on any hit rolls of a 6+. This will make the ScV even better at killing heroes and monsters than the Oldblood.
Due to all these reasons, the ScV is more damaging, more durable, and more versatile in the targets it can effectively engage. As a bonus it is also 20MPP cheaper.
One thing to be noted is that the Oldblood can bank command points in order to mass spam its command command allowing for impressive burst damage. However, the ScV can do the same and remains nearly as effective, more so if the Sword of Judgement is equipped.
Many thanks!
