The two players would have identical OPS. The acronym literally stands for OBP (on base percentage) Plus Slugging (percentage).
They'd both be .850
As far as who's better, they'd be similar but not necessarilly exactly equal, other things could be considered (what do the rest of the team look like - if you got a lot of sluggers, maybe you'd rather have this guy be an on-base guy). OPS is a good stat, but it's a quick-and-dirty method of comparing players only. Don't get obsessed by an 0.003 difference between a couple players as being definitive proof of who's better.