He's good enough for us right now, for sure. If Di Maria is sold and he's brought in, he'll contribute. But paying too much for a 28 year old 5'5 winger is mostly always a bad idea.
On the other hand, we want to win things, we are in a position to do so and if we believe that Pereira and/or Januzaj will become starter quality in 2-3 years then it's not the end of the world to overpay a bit for a guy ready to come in and contribute well immediately until then.
But is Pedro significantly better than Mata, who could do the same? Faster and more comfortable out wide, definitely, but their overall contribution might not be a million miles apart, and unless Mata is going to get serious time as a 10 - and if doing so leaves Herrera out then this is counter-productive anyways - then I'm not sure why we wouldn't just wait a year and buy a winger next summer.
At that point, one of Ronaldo, Reus, Bale, Felipe Anderson, Fekir, Draxler or whoever else either will either become available or in the latter, younger cases, proven themselves a bit more.
Like all intelligent, nippy Spanish AMs or wingers I expect he'd look a bit more creative and impressive in tight spaces in England than people expect, too, and the fact that he's only really finished his 6th season means he should have gas in the tank for the next 2 or 3, but there will be no resale value. He's not going to score 20 goals, but if he gets 30 starts at right wing he'll get 10 and that will help.