Ok. Guys. I've spent some time reading through this thread. I started looking into software looping a couple months ago. I'm in this boat as well. (Boomerang and Sidecar guy)
I acquired Ableton to record my album with and soon discovered I could use it to loop, route audio through effects that snap to the tempo and sync my loops to premade loops(clips) easily. Thus eliminating a very complex live rig of a huge pedal board, many cables, grooveboxes and other toys.
So I played around with Ableton's looper and using Clips to loop. Also tried and failed to host Mobius in 64 bit with jbridge with reliability.
I got hung up for awhile trying to make Ableton behave like the Boomerang. I finally came to accept that this was not currently possible..but there are a lot of thing you can do in Live that the Boomerang cannot do. Ex: For one the flexibility of signal routing is amazing. Your wish for separate volume controls is easily achievable. I now only need one mic instead of two because I can route its audio to the looper only when I want to capture a loop.(no more bleed thru!) I like how "stop" stops the loop at the end of the bar..not right when you push it. That is a preference thing though. play once is easily accomplished by having a dummy clip automate loop off. You can do so much with dummy clips it will melt your brain. Also "stacking" or overdubbing is super easy to set up..no pedal dancing like the rang. One downfall is you need either a double tap or an extra footswitch for "stop". I decided to use two switches for each loop. One for start and one for stop. It's not ideal though. I decided that I could sacrifice some of the Boomerang's features for the flexibility in Live. This would mean changing and relearning my looping style. I decided to roll with it. I invested in an expensive new laptop and a footcontroller. Many hours personifying it. i've also dedicated some of the loop functions to my launchpad mini instead of the foot pedal. I fugured why not? My loops are already running so things like reverse, multiply, clear and mute can be done by hand. Also my pedal only needs to control my guitar loopers. My keyboard and vocal loops are done by fingers on the launchpad now. Anyway I'm still learning and building this system. I need it road ready by the gigging season in May so I have a lot of work and rehearsal to do. I've sold a lot of hardware but haven't made the leap to sell the old Rang yet....Anyway that is where I am at currently