Not 600's but...I have flown the 710's and they are a much nicer feeling blade to me than the MS blades.
The MS blade is less rigid and they will flex a bit under load. So the cyclic and collective are not as crisp as the SAB's.
I have flown the MS 600's a bunch on my Sceadu before I sold it and they worked really well, but I didn't push the ship as hard at night as I did during the day either.
If I flew them during the day hard they were really noisy and a little "soft".
At night they were still noisy, but good enough for my more relaxed FAI kind of stuff I do at night.
All in all if you want a good crisp night blade and don't mind the few extra bucks the SAB's are the way to go.
If you are not that pickey save the $$$ and buy some MS night blades.
Fly Fast....Live Slow...