Off the record, we have learned that Boeing's offer may include a delivery of a certain number of AH-64Ds as a gap filler. Then, as the helicopters are delivered, the aforesaid aircraft would receive the AH-64E Apache Guardian upgrade. Most of the Guardians operated by the US Army have been delivered like so - not from a scratch.
When it comes to the Bell AH-1Z Viper, we know that the US side currently possesses up to 27 decommissioned USMC helicopters (as the Marines are undergoing a transformation, and the number of Vipers remaining in service has been reduced). The State Department also has 12 brand-new Vipers at its disposal, manufactured for Pakistan, that have never been delivered. One cannot rule out a scenario, in which aircraft from that pool are offered to Poland as a gap filler, or even as the final product.
Both helicopters use different design philosophies. AH-64E Apache Guardian is an aircraft that is currently operated by the US Army, including the units on a rotational deployment in Poland. The helicopter features a broad array of sensors - an optoelectronic suite, and Longbow radar. The latter component makes it possible to use radar-guided Longbow Hellfire and JAGM missiles, against numerous targets, including enemy MBTs and fighting vehicles. 30 mm chain gun is the fixed element of the helicopter's arsenal. Apart from the gun, and the ATGMs, Apache can also carry 70 mm rockets. Furthermore, recently Spike NLOS ATGM has also been integrated on the AH-64. Guardians offer Link 16 capability, along with MUM-T (Manned/Unmanned Teaming) system.
Meanwhile, the AH-1Z Viper has been designed to meet the needs of the USMC, also when it comes to remote deployments, with a scarce supply chain, far away from the permanent bases. The platform offers 85% commonality with the UH-1Y Venom. At the same time, it features a modern set of optoelectronic sensors. The Viper is also going to be Link-16/MUM-T enabled. The helicopter is armed with Hellfire and JAGM ATGMs, or 70 mm rockets. It can also carry the AIM-9 Sidewinder AAMs. 3-barrel Gatling gun complements the aforesaid arsenal. The Czech Republic would be the first user of Vipers in our region.
Both helicopters follow a different design philosophy - however, some features of them are shared, such as most of the weapons, or the assumption made for them to operate on a net-centric battlefield. Apache Guardian may use its radar for the detection of numerous targets at once when performing CAS sorties. Viper, on the other hand, has been designed for being operated in challenging conditions, with low supply-chain availability. It may turn out it is easier to maintain throughout its life cycle.
It is not possible to accurately compare both aircraft in the Polish context, based on the available data. The bids comparison may depend on details, such as weapons, the proposed variant, and matters tied to logistics, supply chain, and cooperation between the industries. Both manufacturers have been active in Poland for quite some time now. Their proposals have also been varied.
The Kruk programme has been going on for years now, it is aimed at replacing the obsolete Mi-24 helicopters that lack any guided anti-tank systems.