never used SEM, but I redid the entire interior of my Rubicon in 2012 with the DupliColor line - I did the dash, doors, console, seats, and carpet. the dash/doors/console still look like it came from the factory that way. the cloth seats are a little faded (which I knew would happen from sliding in/out of them - it doesn't show on clothing, except maybe white pants). I'm pretty anal and I think the seats still look fine, all things considered. touch-up should be easy, though. when I first did the seats they felt stiff, so I "buffed" them with an old pair of jeans to soften the dye/paint. the carpet I brushed soft with a nylon brush.
when i first considered it, i found numerous failures on the internet using this stuff, but saw some success stories. as with most failed internet projects, failure usually results from poor execution - the tool is always blamed before the inept user:
I believe the key to hard panels is using the PREP SPRAY and applying numerous, very thin coats.
a factory-look on fabric can be achieved with slow, tedious, perfect taping at the stitching and piping. i also think it helps to remove the covers and run them through the washing machine to get any body oils off. carpet needs to be scrubbed and rinsed thoroughly.
on two-tone seats, overlapping the previous, lighter color for a couple light coats (then re-taping at the intended edge) can help hide the old color at the seams and within the stitches.
you wouldn't know it, but I also used VHT last spring to change the color of the middle strip on my swim deck cushions that a previous owner replaced. i prepped the seat with a very light wipe of acetone because i didn't have the prep spray.
@Blazin14 not sure from your pics, but is the SEM Sail White a bright white or a slightly off white? it looks bright. I just bought the VHT White Satin to redo a used bow filler cushion and touch-up some other cushions, but it is like super-bright snow white and doesn't match ...though it does match the gelcoat!