I've got both a Tikka T3x SS in .300 Win and a Sauer 100 XT in 6.5 CM, both purchased last fall. The Sauer, IMO, is every bit the equal of the Tikka in terms of accuracy, fit and finish. Accuracy wise, both are sub-MOA shooters with both my handloads and factory loads, the 6.5 CM probably a bit more accurate with factory loads just because of its chambering. The Sauer feels like it has a higher grade polymer stock and I really like how it feels, however, it has a LOP of 14 9/16" which I find just too long even though I am 6' 1" and the Tikka just fits me better. Also, while both come with a pretty hard recoil pad, it is easy to switch out the Tikka's for a Simms Limbsaver, which I have really appreciated on the .300 Win. I don't think Simms makes one for the Sauer and I'm glad it's in 6.5 CM.
Both have outstanding triggers that are easily adjusted without taking the action out of the stock. I have both set at 2 3/4" pounds and they break like glass, but I like the feel of the Sauer just a bit more. The Sauer also has a flush fitting 5-round magazine, whereas the Tikka is a 3 round magazine even in non-magnum cartridges. The Sauer is about 1/2 lb. heavier than the Tikka, some of that weight I attribute to the longer stock and the fact that it has a metal trigger guard rather than polymer like the Tikka. The Sauer is finished in a semi-glossy blue, whereas from what I recall of the Tikkas, they are a matte blue, which I would prefer if I did not have the stainless version.
Regarding the safeties of each, the Tikka has a 2-position and the Sauer has a 3-position. Since the Tikka locks the bolt in the "Safe" position, I really don't have a preference, I guess if pressed I'd choose the Sauer's 3-position. The actions on both are super smooth, with the Tikka's bolt being slimmer. The Sauer rifle is backed by a 10 year, sub-MOA for 5-shots warranty and I don't recall what Tikka's warranty is.
All in all, I've been extremely pleased with both rifles and they both are my best shooting rifles of the several high-power ones I own. A guy could not go wrong with either rifle, but if I could only keep one, I'd choose the Tikka because it's 1/2 lb. lighter, stainless steel, has a better recoil pad and has a LOP that makes it quicker to shoulder.
I own both as well, and this statement above is spot on.
I have 223 and 06 in tikka, the sauer is in 9.3.
To find a soft recoil pad for the sauer was a M Fer. That tells me as of now, Tikka has much more after market parts.
The synthetic stock on the sauer is VERY nice, but honestly I have not felt new T3X.
Even thought the action might be a hair slicker on tikka, the sauer feels like its gliding on rails and feels stouter.
I don't think you can go wrong with either one.