Not a bad deal at all for the Astros...
Not even an overpay.

Brian McTaggart is an Astros beat writer but Mark Berman works for Fox 26 sports in Houston and has very good inside information. Not sure who to trust more. Berman breaks the big stories faster than anybody I know.

I haven't seen or heard a fourth player involved yet, but the third player involved is outfield prospect Derek Fisher.

Mark Berman ‏@MarkBermanFox26
Told #Astros getting closer Ken Giles from Phillies for pitchers: Vince Velasquez, Bret Oberholtzer & OF Derek Fisher, pending physicals

http://m.mlb.com/prospects/2015?list=hou

That link shows our best prospects. Daz Cameron and Kyle Tucker, were just selected by the Astros in the 2015 MLB Draft.

Derek Fisher is a good outfield prospect for the Astros but we have so many and drafted many more in the recent MLB draft.
And this was after we had traded Brett Phillips to the Brewers in the Carlos Gomez and Mike Fiers trade last July.

Ken Giles has a career 1.56 ERA in his two seasons. The lowest in baseball history (minimum 100 innings pitched).
Giles threw 193 fastballs at 98 mph or higher in 2015; Astros relievers as a group threw eight, the lowest in baseball.