The NGQ ain't gonna make your rig push 4 people and a cooler anywhere you want to go period. I got a 2-seater and I have a weight limit for riders. I carry a small cooler, sometimes I have to drink warm beer and have even been down to hot water every now and then.
There is a small margin of gain to be had with a new generation of prop, but you would be way better served focusing on the load. Pick the heaviest of the 3 riders you are looking to carry and get them their own boat, then you can carry 4 folks with 2 boats anywhere you want to go, it's more fun that way anyhow.
I run the NGQ, 2 blade, 74" cut down to 72" (i.e. winglets removed) on a AV 540. I love the prop and it does push great. I have used a Q and whirlwind whisper tip (both 72") previously and find the NGQ works the best for me.
I find the NGQ works best for me by keeping RPMs down on ground and pushing the best from a dead stop (i.e. pushes down low). That said, the boat ran where I want with any of the previous props, the NGQ didn't change my decision making (not always optimum).
Those WW Sig props work just fine. I wouldn't change it for your described goal, but I would start thinking about how old it is and just how many "close" friends I need.
I think Jon and I have different measures of "performance", and that's cool.
My experience with the 2 blade Whisper Tip and the older Q is very similar (they are both 10-1/2" wide blades, that Sig and NGQ are closer to 12). They push really well, spin up quickly and give 60+ top ends. Switching to the NGQ I found that spin up/response became more linear, which made the boat less "jumpy" so I can hold a more constant RPM on ground and operate closer to 0 without actually stopping. I do feel I netted a bit more (~5%???) thrust at WOT stuck on ground, but I gave up top end speed/thrust (55 MPH top end now).
Since my son gets my hand me down's, he ended up with the 72" whisper tip when we sorted out who runs what boat. He described the difference the best, the whisper tip let's him spin it up quickly when needed to keep running through the black mud etc., and the boat fly's, but starting from a dead stop the NGQ wins. He wants an NGQ but hasn't sent enough heavy vegetation, beer cans, pocket knives etc. through the WT to make it worth coughing up the cash.
Me, I'ma cruise control sort, make me
I always thought those WW Sig blades looked like clubs and must have been designed by Bam Bam from the Flintstones. But that doesn't mean they don't work good for the purpose.
Whatever you do, stick with 2 blades if the goal involves a load and ground.