I had both (Tikka T3 Lite 6.5x55 and Sauer 100 XT .30-06) and its a tough choice, my opinion:
Stock: equal quality and stiffness, the Sauer shape is nicer to me but thats entirely personal. I like the negative comb and wish more makers would use them. The LOP on the Sauer is long, but I am tall with long arms. The T3 and Sauer have harder recoil pads, the T3x is softer. The stock is hollow, so is loud when bumped. The Sauer stock is much better at reducing felt recoil, IMO.
Magazine: the Sauer holds 5 and is flush, the Tikka holds 3. The Sauer can be loaded through the ejection port, the Tikka can't. No winner ITO mag latch and seating. Overall I pefer the Sauer mag set up.
Action: Tikka is a smidge smoother, in travel and when locking into battery, but Sauer is still smooth and mine only had about 40 rounds through it. The Sauer needs a bit more force to lock into battery and is not as fluid, it pushes against the bolt release spring which makes it feel likes its catching on something. Sauer has a much bigger ejection port than a T3.
Trigger: both are very good but the Sauer adjusts to a slightly lower pull weight, at least from what I can feel (not measured).
Bottom metal: Sauer is aluminum, which I think is nicer than the Tikka plastic, but the Tikka hasn't presented any problems.
Safety: I prefer the Sauer 3 postion but nothing wrong with the Tikka 2 postion.
Accuracy: can't tell the difference, both are excellent, both shoot well sub-MOA with loads they like.
Weight: Tikka is definitely lighter, although the Sauer isnt exactly 'heavy'. In .30-06 I preferred the weight of the Sauer. My T3 with Talley Lightweights is 7.1 lbs with a VX3 2.5-8x36. Same scope on the Sauer Classic with weaver bases and steel Burris signature rings was 7.75lbs. A good weight IMO. If you want less weight, the Tikka will be lighter.
I sold my Sauer but only becasue I wanted to fund something else. I would happily have another one. I think it would be a sweet rifle in 6.5x55.