I've never understood the point of the Greyhound. Friggen 60 fuel and it sucks against a Luchs.
The Greyhound starts slow but at Vet 3 is really good against infantry. Vision on it is great at Vet 3 also as is its AA.
My biggest complaint about it is that the CP requirement makes it arrive so late that it is hard to vet up against good opponents, or even against mediocre ones in 4v4's. The Puma just requires the light mechanized company which is more the equivalent of having the LT or CPT dispatched or possibly an officer plus side tech. It somehow got overlooked when the balance team was addressing the no-tech callins.
Cannister shot has such a long delay that it is worthless, unless your opponent likes to go AFK a lot. They brought it back in name only. It's also badly overpriced for as little damage as it does, which is small compared to similar abilities like the OST sniper's vet ability. Even without that ability, I'd use it a lot more if the call-in requirements were fixed.