Undertaker will win it. Contrary to other opinions, Taker beating Lesnar will have no ill effects on Lesnar. Even though Taker is older and way past his prime, losing to Taker is not a black mark on anyone's career. Lesnar will go on being Lesnar and go on being the most intimidating threat in wrestling.
I can't see Lesnar beating Undertaker simply because it would seem odd to bring him back for this to simply lose again. Plus keep in mind that the person deciding the outcome for this match is the same guy who booked Lesnar, a guy who didn't need to break the streak, to break the streak.
I think after basically being dominated by Lesnar throughout his career, Taker will come out on to.
But also like Serina mentioned, the buildup will be better than the match.
- Oh yeah, Taker beating Lesnar at SS won't have as nearly as much effect as Lesnar defeating Taker's Streak at Mania last year.
Taking away something that's 21 years old was huge, now Taker coming back for his revenge won't leave a black mark on Lesnar's career, as you pointed out.
- Taker being brought back to lose would be ridiculous, not that I'd lose sleep over it or anything. We talked about this during Mania season, Taker wasn't gonna work WM 31 just to lose his match against Wyatt and he didn't. I think the same scenario will be played out here.