I'd rather have Koji Uehara than the bigger-name reliever on the market, Heath Bell, and the Texas Rangers managed to acquire Uehara without giving up a top prospect as they would likely have had to do to get Bell, while the Baltimore Orioles get two interesting fliers who no longer fit in Texas.
Uehara is an extreme control artist who survives with a fastball that tops out around 90 or 91 and mostly sits in the upper 80s. He locates it extremely well and offsets it with an above-average splitter that doesn't have the sharp "bottom" of most splitters, but that always moves down and often ends up right at the hitter's knees.
The combination of those two pitches and his ability locate them so well gives him very high swinging strike rates despite the lack of velocity. Uehara is, however, fly ball-prone, pitching up in the zone with a fringy fastball, and while a huge percentage of those fly balls are popups, enough are true fly balls to the outfield that I'd be worried about his home run rate in a good hitters' park like the Rangers' home field. He'll help them, but it's more about building a postseason roster than getting the team to the postseason.
For Baltimore, they get a worthwhile gamble in Chris Davis, who needs an extended opportunity in the majors to show whether he can make enough contact for his power to play. He's shown he can destroy Triple-A pitching, and in limited duty the last two years he's at least made more contact against right-handed pitchers in the majors. He's a good athlete with plus-plus raw power, and he might be able to handle third base, although first is most likely.
However, he has a number of issues to resolve to be able to hit even .240 in the big leagues, from the lack of a real two-strike approach to pitch recognition problems that lead to so many of those two-strike counts in the first place. He's exactly the kind of player a bad team like Baltimore should put in the lineup every day for a year to see if he can succeed when he gets regular playing time in a zero-pressure environment.
Tommy Hunter is most likely a reliever, as he lacks an out pitch and has particular trouble with left-handed batters (.290/.356/.486 in his major league career). In the 'pen he would likely sit 92-94 and touch higher than that, although I'd like to see him go back to using the power curveball more and relying less on the cutter that hasn't solved his problem with lefties anyway. I think he'd be stretched to succeed as a starter in the AL East with his current repertoire, even as the last man in a rotation.
It's a fair return for two months of a reliever, but unless Davis turns at least one of the corners in front of him it's not likely to cause Texas any regrets.