Mrjonsong Damir let me know how you like it. I’ve always mixed my tracks in Cubase and just used a stereo WAV for my backing tracks. I am looking forward to tweaking the mix with individual stems in the mixer.
I bought it because i am thinking of going multitrack as a solo artist i don't really need it but if i find ST4 worthy to do so i will, the mixer is very compact and easy to setup , you will be able to use 8 stems in view at one time but is easy to swap to the other 8 , i think its perfect to use with ST 4 having 16 Chanel's , the mixer is nice sounding and has lots of great tools on board like feedback exterminator ,  4 FX BUSES, easy gain setup on the inputs and lots of other normal stuff that works as expected , i love the fact it has 3 assignable knobs and a large knob that can be also used for whatever you need , i have my mic on one my guitar on two my backing on 3 and the master volume on the large knob , i run very simply with this mixer its a huge overkill but its small great sounding and gives me four knobs to control.
I could easily do an average band on this  little beast with all the niceties required i have an XAir 18 mixer which is basically the same as this one but i decided i wanted knobs and a touch screen built in thats very powerful and reliable , so far it hasn't given me grief but its early days, lots of good feedback from others so i am confident it will be a good investment to use as an interface in studio and a mixer on stage, too many other features to mention but i haven't managed to find any bugs on it yet   , i like it , with more use i think i might be saying i love it but not for now its still too early , just like ST4.
Good luck with it if you go that way.
Cheers Damir