it's a moltke on drugs, plain and simple.  it has good firepower, good range and is rather robust.  it can be used with or without AA or with the SD-2's instead of the dual 10" guns.

Never ran both together since i only have 1 set of gunners but the petro is very fun and one of the best PCA's a little OP but it is less OP than a mandel by far.  i would definatly say it is better than a moltke in the right hands though. 

Only by a little though since you can still fit the 4.1" AA guns on the moltkes T slots.

i had two sets of gunners when i had mine two +12 accs and two ebve reloads so i ran AA as well as either 10 inchers or HH on the R slots and generally the 3.1 minizi's on the T slots. The miniz's are a great aa gun provided nice reload and medium range with medium damage. the 5.1s hit harder and have more ranger but much slower reload and very limited shells. its a great ship with high lvl gunners but if you are a lower lvl player its a harder ship to play because that spread is rarther bad with as is reload at lvl. but its still a great ship.

I still use it with SD-2s to level most of my sailors to 60, the range, ROF and damage of the SD-2s suits me just perfectly, but you do need good reload gunners for them really, mine are lvl 105 now, I cant remember when I was last used to them being slow.

I have also used a moltke, which obviously provides a combination of excellent ROF and damage with relatively good range, but those guns are better compared to the Minizinis, which do slightly more damage with about the same range but twice as slow.

Its an excellent AA ship, SN AA is very good, SD-2s for range, Minizini for short fast fire.

Its much better than the svetlana, more dp, more total T slots at better angles, actually able to USE the SD-2s. The PCAs are all pretty much designed to be very good AA boats, it even says that in their item store descriptions. Obviously they arent all very good, but the Petropavlovsk, Motlke and Asama are all very good AA ships.

How it compares to the motlke is based on which guns you use imo. If you use the stronger, slower, long range AA I prefer the Petro, if you want the short range, fast firing AA, the moltke is better.

The Petropavlovsk was originally a Prinz Eugen class Heavy Cruiser (or Admiral Hipper depending on if you consider Hipper/Prinz Eugen same or separate classes) but the Germans sold the hull and plans to the Russians while they were allies. I always forget if it was named the "Seydlitz" or "Lutzow" originally but I believe it was Lutzow (not to be confused with the "Deutschland" Pocket Battleship whose named was changed to "Lutzow".  Actually, I'm pretty sure the Seydlitz stayed in German possession because reconstruction began on it to convert it to a Small CV but it was never completed, like most of the Kriegsmarine.

In any event, the Petropavlovsk seems awesome!