Hmm. Some of this is true but I never saw 1st class immigration. Possibly you get in line first, but often there's an A380 worth of economy passengers there from another flight that landed 30min prior.
Re-entering the US for US citizens, Global Entry. And, yes, getting off a plane first is usually an advantage for clearing immigration though not guaranteed to breeze through.
In general (leaving aside flying private) paying more money doesn't necessarily buy you a lot of time savings (especially if you're not the sort who tries to cut things close) but it can eliminate a lot of hassle/buy you a lot more comfort which is probably more important to me most of the time.
Priority bags/check-in does help but I try not to check luggage so really doesn't save me a lot of time at the end of the day.
