I talked about it in here 
I use it all the time it’s a favorite ! it helps me to deconstruct a loop where I have 3,4 parts inside to help me with track construction so I can get out a part and get in etc… I’m not stuck in the loop. sometimes it’s gives interesting results sometimes you have a little more effort to extract things as you want - there’s also XTRAX STEMS, and Zynaptiq Stems (within Acid Pro last version you can’t find it standalone it’s within Acid Pro)
But to me the real value is in Regroover Pro
I can do without the others