Okay, so the Rangers have the exclusive negotiating rights for Yu Darvish. We know he's a righty pitcher. We know he's 25. We know he's supposed to be really good. But what else is there?
To help out, I'm going to offer a thumbnail scouting report on Darvish. I offer this with the caveat that I haven't watched him, don't know any of this personally, and basically and summarizing and aggregating the reports that are out there.
So...Darvish is listed as 6'5", 215 lbs. You can see his full stats for the Nippon Ham Fighters here.
Darvish throws a two seamer, four seamer, and a cut fastball, with the four seamer supposedly getting up to 95 mph. He also has a slider and a curveball, along with a changeup, although it is questionable whether his change will actually get much use in MLB, as it seems to be his sixth best pitch.
He throws hard, he strikes guys out, and he gets swings and misses.
What remains to be seen is how this will translate to the U.S. Japanese hitters tend to be less selective than MLB hitters, with the result being that Japanese pitchers may seem to "nibble" when they come to the States, since they are used to being able to get batters to chase balls out of the zone. Without a changeup, I guess you could worry about how he would fare against lefties, but his cut fastball is supposed to be good, and a cut fastball is a good weapon against opposite-handed hitters.
Given the fact that Darvish is going to require a commitment of $100-120 million over 5 years, I think it is safe to say the Rangers' front office views him as a legit #1 starter.