Zara is a brilliant PCA. The 50 degree high angle guns it comes with can be a bit of a pain with the angle, and the huge range meant my ebe bo could never see where shells landed, but the damage is huge and the reload is great.
It's not like the motlke or furious, etc, you're not going to hit like a BB. But 8 barrels doing 700 damage a shell every 3.5-7 seconds wrecks basically everything that you can hit in seconds, with lots of room to compensate, unlike 10s reload BB PCAs. It's also very tough and fast, but once you buy it you need to change its engine and FCS since the ones it come with as standard arent the optimal. (It comes with CA FCS but can use BB, and it comes with CA engine but the RM CV engines are better)
As for the PBB, the AD was a brilliant KM PBB... I'm sure the RM one will be just as good, all the PBBs are really.