I own a pair of the smaller (ISIS) Innersound speakers and before I bought them I auditoned the Martin Logans, Quads and Magnepan 3.6Rs. Never heard the SoundLabs, but haven't read anything negative about them.
I chose Innersound because they integrated woofer to panel better than Martin Logans, played louder than the Quads and were more available than the 3.6Rs (At the time there was a 6 month wait for 3.6Rs). My overall preference/ranking of the 4 is:
Magnepan 3.6Rs
Innersound
Quad
Martin Logan
You need to listen to as many as you can, and don't forget things like associated equipment, room size and WAF (if appropriate)
I chose Innersound because they integrated woofer to panel better than Martin Logans, played louder than the Quads and were more available than the 3.6Rs (At the time there was a 6 month wait for 3.6Rs). My overall preference/ranking of the 4 is:
Magnepan 3.6Rs
Innersound
Quad
Martin Logan
You need to listen to as many as you can, and don't forget things like associated equipment, room size and WAF (if appropriate)