SASless - The P8 discussion has had the backside well and truly kicked out of it in the past, and the incumbent USN MPA is not likely to be as capable as the MRA4. If for no other reason than a twin-engined aircraft will offer up some serious low-level performance questions, in the event of single engine failure. A quick search using the facility at the top of the page will allow you to trawl through the arguments for and against.
Party Animal - You can't even hope to compare the UK's maritime commitment to that undertaken by the Dutch. I have no doubt that we will make do during the gapped period, but the capability will be missed. What the fleet really needs is the feedback, from the organisations that would normally have a service provided by the Nimrod MPA, to report what effects and to what extent the lack of support is having.