Hello falcon 120,I'd be Happy to....
For Me going from Rift to Pimax was a noticeable difference.
--FOV--
This was the first Big difference I noticed,It was like going from looking through a periscope to having a panoramic picture in front of you.
--Resolution--
Very noticeable difference here as well,Hornet DDI'S,MFD's,HUD,Small Analog Gauges all much better and readable compared to Rift.
--Target Spotting--
For me it's a little better,It could be my Pixel Density is set too high to spot far away targets.
--Drawbacks--
Their is some distortion at the very edges of the lenses,Noticeable when doing Carrier Landings and you're making the long left sweep turn to final while trying to keep the carrier in site.
--Demanding--
It's very demanding on hardware...You'll need plenty of PC Horsepower to run it at max,
--Comfort--
The Pimax headstrap is not as user friendly or adjustable as Rift's,Some user's actually complain of pain after long missions.
These are just my personal observations after about a month of use.
Hope this answers some of your questions.