So I dont care much for ravs and I'll try to give my unbiased take on them.
Base strain
Ok so we got empower, which gives a health bonus. How much? Who the fuck knows? I'll get back to you when I have a few hours to flush down the toilet as I die again and again to see if this is worthless or not. No other skills so there is not much going for the base strain. You have a kinda slow xeno with average health, countered by marines walking backwards.
Hedgehog strain
You can shoot bones. I am not sure if this does anything, the cooldown is kinda long and I've never seen anyone go down to it and it doesn't hurt the tank. I guess it's a way to pass time until you are ancient so you dont die during a single room-wide HEDP stun. Spinslash is good on the other hand. I guess this is the best strain at the moment.
Veteran strain
So the nerf put old rav charge into this strain except you dont have armor because ravs were too strong or something? The charge would be good if most better than average marines would not dodge it, but they do. If you miss your charge you basically committed suicide in a fancy way as you are next to a bunch of marines who can kill you even if you slice the shit out of them, as I have seen marines stand up a few moments after being de-legged and keep buckshotting. With the charge on cooldown you have a xeno that is, once again, fully countered by walking backwards and shooting.
Keep in mind that ravagers barely have any evasion so not only are they slower than their smaller sisters, it is also enough to vaguely shoot in their direction to kill them.
Ancient Rav is actually playable because it has speed so you dont have every PFC styling on you.