BUD53
Contributor
Swapped my rig around from an s600 primary & 550 backup, to the 600 as my backup (550 around my neck wanted to free flow a little in strong overhead currents. I can tune the 600 down), and an s650 for my new primary. with 2 mk17s for my 1sts (formerly used a mk25 but went with another 17 because I primarily dive wrecks, caves and quarrys and the 17's are sealed). MAN, .....the 650 breathes -EASY-!!! When trying it out before even diving I could tell ALOT of difference. I had no problems with my 600 but this 650 is almost like there is no regulator. I may find some hangups later, but right now this reg is on my list of AWESOME! 
