The thunder of 4x spey is better than any other sounds
Unless its four Pratt and Witney Twin Wasps
But best of all is (alas now was) 4 Griffons.
Seriously though, Royalist is right - factor in range requirements, tasking, weapons, comms, search times etc and each will give you different answers. The Shack was a marvellous aircraft for almost any maritime role - for its time. But space was cramped, noise (particularly sitting alongside the propellors) you learnt to live with but did hearing no good at all and overall crew comfort/working environment - with hindsight - quite poor. The Nimrod gave a massive improvement in almost all aspects, and the P3 gave a similar boost over the Neptune.
Propellor driven ac will be relatively cheap but probably shorter range, jets have better range and can probably carry a lot more kit and weapons but would be expensive overkill for the more mundane tasks.Rotary or even airships could be factored in for some over water tasking, so don't automatically assume it has to be a fixed wing platform.
You pays your money and takes your choice!