The T-850 far outclasses Guts in lifting strength to the point of being able to dominate him if the two of them were to grapple in melee. (Which all of the Terminators tend to do) He should also have more than enough strength to crush Golden Age Guts's sword, seeing as it was shown being chipped down by common blades wielded by everyday human soldiers and every form of Terminator has been shown smashing various forms of metal with their bare hands.
Scanners and targeting systems within both the T-800 and the T-850 allow for prediction of a target's trajectory as well as location of weak points and assessment of all weapons within the target's possession, all in a matter of moments. (read: he will know where Guts is going, every weak point in Guts's armor and every weapon Guts is carrying, at all times) Trajectory prediction features and in-house targeting systems are accurate enough to allow the T-800 to incapacitate a group of numerous police officers (as well as destroy several police cars) using a fully-automatic Dillon Minigun at full-burst, without any casualties whatsoever. Also allowed the T-850 to perform the same exact feat with a heavy machinegun.
Other features found within the T-800 and T-850 models include infrared vision (allowing them to see enemies in extreme environmental conditions), X-ray vision (allowing them to see their targets through any solid material, including several-inch-thick walls made of solid concrete), and monitors which assess the target's vital signs and bodily processes such as heart-rate, breathing rate and subtle muscle movements. The latter allowed the T-850 to predict the exact probability of John Connor following through on his threat of suicide. (Or, more accurately, the exact probability of him pulling the trigger on the gun he held to his own head)
Terminators do not feel pain or fatigue, and will continue to fight as if unimpeded when missing skin, limbs or even whole sections of their bodies.
Both the T-800 and the T-850 have shown to be capable of fighting Terminators who held the advantage over them in terms of weapons and abilities as well as scanning systems similar to their own, winning against most in single combat and holding their own against others. Guts doesn't even have better weapons in this fight.
And let's not forget, Guts's main style has always been to rush headlong into the fight, powering through damage with his obscene endurance and stamina. He thinks on his feet when the time comes, but he's never been much of a tactically-minded individual and the manga makes this clear numerous times throughout its run.
All things considered, I gotta go with the Terminator on this one. He has all the right advantages here, and even with Guts's infamous brutality and stamina, it's only a matter of time before Arnie takes him down.