The black one looks a little more used but looks good higher miles. OH that rear shock is one size fits all solution!!!
Red one looks good lower miles clean so really depends on the price.
Paralever is guranteed to go out could be 1000 miles from when you buy it or 1,000,000 miles.
Your a wrench geek - put it on the centerstand and rotate the rear tire - you will know if something is wrong right away.
My 89 GS with Paralever is great to many horror stories
about them failing gives it a bad rap!!!
That said the Red one with lower miles - much cleaner and a motivated seller is the way to go!!!