There's no doubt that Murray accomplished more than Wawrinka when you look further than the slam count as Andy was a very consistent performer for almost a decade even before he started to win slams. Wawrinka was obviously a late bloomer, his match against Djokovic at the AO in 2013 is what put him on the path to bigger things even if he lost that one. However even in the years that followed, outside of slams, he was quite the roller coaster while Andy was consistent week-in/week-out which is why Murray won more titles and MS-1000 events than Wawrinka ever will. From that point of view, it is hard to compare the 2 careers because they had very different paths, but again no doubt Andy has had the superior career.
Now if we're talking about peak level of play only, I think Wawrinka is the more dangerous opponent. He's pretty much the only player that's been able to edge Djokovic in his best years during slams which is something Andy hasn't really ever done as convincingly (depending on how you see 2012/2013 Djokovic). When Stan is firing on all cylinders, he's very hard to stop on slow surfaces. From all my years watching tennis, I don't recall seeing a Murray performance against top level opposition where he dominated or bullied his opponent the way Wawrinka has done on a few occasions. Of course they both have different styles and Wawrinka is the more offensive of the 2, but from a peak performance perspective, I'd pick Wawrinka over Murray.
