Bear in mind that if it follows tha M version the SA1 will NOT have the trigger guard safety, which I think is the niftiest safety out there - although the HK P7 is also pretty cool I confess.
The only reason I don't intend to use this if I carry the Steyr (only got a holster for it yesterday!) is to make it functionally the same as the Glock 19 and Kahr PM9 I also carry - so muscle memory can take over under stress and not vary. If the S9 were the only gun I'd ever carry I would keep the safety on as an extra precaution as it really is slick to use. I still practice with it on at the range and have no trouble getting the shots off in the same time as the Glock (actually marginally faster because I'm better with the Steyr sights) wven disengaging the safety as I bring the gun to ready. However as has often been said targets aren't firing back.
I have a XD9SC, it's really nice but not a slim as a S9.
I have XD40SC mags for it and it now holds 12 rds, not bad for a pocket rocket. Also, I have a few of my friends shot it and they couldn't believe how soft it shoots. I think the dual capture recoil rod have something to do with it.
Very good accuracy from a 3" barrel. light weight and excellent warranty. SA has a package deal now where you can get a SC with two 10 rd, a regular full size 14rd mag with extension/pinkie grip, and a holster with it.