Well I must say I’m beyond blown away by SL10 Unmix Song feature! I’ve been using SL 8.0.10 to unmix live vocals from the mic bleed (mostly cybmbal and drum bleed) and it’s done a pretty decent job up until now. I had an issue when it was updated to 8.0.20 that made the process take 7-10 times longer. Between SL8.0.20 and on to v10, the speed difference is not that great, but the QUALITY of the audio is UNBELIEVABLE! Here’s my test results:
24/48 wav file - 4:48 minutes
SL 8.0.10 - 0:13 render
SL 8.0.20 - 1:35 render
SL 10.0.2 _ fast mode - 1:40 render
SL 10.0.2_Best - 5:00 render
So the times are atrocious comparatively, but the difference in separation is what I’m really impressed with. That being said, I compared Fast mode to Best quality mode (SL10) and again, the difference was small (quality of result). There was definitely a noticeable difference for the discerning ear so if you’re wanting the BEST quality result, “BEST” is worth the extra time. 
I didn’t notice as much of a difference between Fast and “Regular” however. But all material is different so your mileage may vary…
Like I said, I use this feature to de-bleed live vocal mics (which this feature excels at). I do LOTS of live recordings and mixes and running 8.0.10 on a 2 hour + file takes about 5-8 minutes. In SL 8.0.20 and later this takes about 45mins to an hour! If I’m de-bleeding 4 files, you see where the time saved is HUGE.
Anyone interested in this for de-bleeding live vocal mics, I just uncheck everything except vocals and then mute that channel and export.
Running this process in SL8 vs SL9, the quality difference is negligible. When I say that, i’ve done a comparison by importing both to the DAW, flipping the phase on 1 track, and the meter shows the difference at -160db. That’s really, for all intents and purposes, no difference at all. None that you’d ever hear in a mix, no matter how sparse.
The test I conducted was on pretty much a worst case scenario. Client sent me live recordings where the vocal mics were about 6-8 feet in front of the drums. Closed room. When I ran it in SL8 and completely dumped everything but the vocals, there were still some drums in the background when the singer was singing. Enough to make an audible difference.
Running it in SL10, there were NO DRUMS LEFT! None! I mean they were non-existent behind the vocal. I’ve tried a lot of tools (RX10, etc.) and nothing even comes close to this kind of separation. The artifacts were very minimal as well. Acceptable when you put them back into the mix.
Kudos to the Spectralayers team for this upgrade in quality! I will be upgrading this ASAP and keeping SL8.0.10 for when I need something fast, but SL10 is my new goto.
Secret weapon just got an upgrade! Shhh