I might be as biased as one can be, since Andrus, Beltre and Feliz (and Salty and MaxRam) are all among the 15-20 prospects on my little simulation roster (stop copying me JD), but with all disclaimers (years before they help the club, undeveloped tools, etc) as givens, the Rangers have collected some pretty special talents here.
Andrus was one of four 18 year olds to-be on Baseball America's Top 100. The others, Billy Rowell, Jose Tabata and Fernando Martinez, have all battled injuries and questions on their status as well, given the level they are all at for their ages. Also, all three are corner players with less positional value, and none are considered even decent defenders. But that is some high cotton for a prospect, being in the middle of those sorts of names.
Beltre, who has survived but not excelled as a 17 year old in the GCL, was considered to be one of the two or three most talented guys in a class that included Carlos Triunfel, Angel Villalona and Beltre's ex-teammate Oscar Tejeda, among just name after name of promising kids. He has special physical talent with a power projection through the roof, good speed and arm, and some semblence of patience at the plate. To my knowledge he was the only player in minor league baseball last season who was publicly compared with a young Barry Bonds and Darryl Strawberry (by someone outside of their - and the Rangers - organization, no less). He surpasses any of the Rangers' highly regarded signings in the past two Latin classes, and you know that AJ Preller, for one, was excited to get another shot at him.
Feliz, simply, has one of the best arms in the minor leagues. We've fortunately advanced as a baseball community past starting and stopping with fastball velocity when we discuss pitching prospects, but when it comes with some promise on a curveball and quality initial performance, it is noteworthy. Feliz is one of a handful of raw but promising very hard throwers in the lower levels in whom I had particular interest.
These guys, especially Andrus but really the other two as well, are household names among people who follow prospects through all levels and are three of the elite physical talents to come from Latin America in the last few years.
I'm really excited to have each of them, because, as Adam mentioned below, they aren't Jim Bowden decathletes who have no ability to play baseball. They are baseball tools guys with depth to their games.
Also, a miscellaneous point that has probably been mentioned on here but that I haven't seen or heard yet today. The Rangers have traded for four pitchers in these deals, and three of them are lefties. In updating my personal organizational depth chart one thing that had been jumping out at me was how weak they had become in left handed pitching. And while none of the three are big studs at this point, they are all prominent enough to make a real difference in the quality depth at that spot, with one at each tier (MLB, AA, LA)