The second hand price has been pretty stable here (UK) for a good couple of years.
I sold mine for about £550 after having it for about a year (I bought it in a NI sale for £650 a few months after it was released).
It’s probably worth waiting to see what NI announce about Traktor. There may be a load of them up for sale afterwards if they announce their next big thing, who knows.
It is a really good bit of kit, total luxury for doing a bit of simple mixing at home but as phelios said, really big for carting around for gigs.
I never really got into using the stems side of things that much and found using the sampling decks for capturing loops a bit fiddly to be honest, so I was probably under utilising it a lot.
I tended to use 3 normal track decks and one external input for a synth or drum machine.
It’s pretty great for that type of setup.
The screens were great - good enough to switch the computer screen off, as long as your music is nicely organised into playlists. Really the only things you need to refer to Traktor for is searching for tunes outwith your playlists and hitting record to record your mix.
On the downside, apart from the huge size of the unit, I found a few strange design choices
No dedicated tempo control was very strange for a dj controller. You have to go into a menu for manual tempo control - very odd.
Obviously NI expect everyone to use beat sync, but if you want to do a bit of manual mixing or mix into a vinyl record it’s a bit clunky. It really is a machine designed for mixing 4/4 techno.
The lack of customisation options was the one thing that really annoyed me about the S8. I thought the whole point of using a computer to DJ was be the ability to customise your controllers to your personal style. I naively thought that NI would allow customisation of the S8 in a Traktor update, but it never came (I haven’t checked for a while - it may be possible now).
For example I wanted to map the EQ controls on the mixer to control the Xone 92 filter effect, to set the mixer up in similar style to a Xone DB4, but that wasn’t possible.
Also, the 4 band Xone EQ mode coudn’t be mapped across the EQ and filter controls on the mixer - a definite oversight.
Some MIDI mapping of the Stems controls is possible, but most controls can’t be reassigned.
It’s pretty much down to personal taste and your style though.
Ultimately, I sold because it was taking up too much space in my fairly small setup. I still miss it a bit, it was a lot of fun!
Anyway, enough rambling, just though I’d pass on my experience.