Other than just looking as cool as can be, the Staghound is a big upgrade from the Daimler I. The stat line looks like this (click the pic):
Now, this may not look like much to some, but this a BIG upgrade from the Daimler I. The Staghound has 2 more Front Armor, 1 more Side Armor and an extra MG. The HQ Staghounds are 55 points each, with the 2 HQ added Staghounds only 45 more. For 5 more points, an AAMG can even be added! The overall cost is just slightly more than the Daimler I and very much worth it, in my opinion.
With the upgraded armor, shots from those pesky HMGs are totally survivable. Enough shots at FA 1 with small arms WILL bring down a Daimler. The side armor of 1 also makes assaults a little less scary, especially with the new-ish V3 rule about 2 tanks teams in defensive fire.
I did these guys up pretty worn and dirty. They are Irish Guards! I need to go back and add in the antenna for the radios. These shine in these pictures, but do not in person.