Feldman, 2013:
181.2IP, 159H/78ER, 3.94 ERA/1.09 WHIP
132K:56BB. 105 ERA+. 2.36 K:BB ratio
Feldman, 2011-13:
337.1IP, 323H/162ER, 4.32 ERA/1.25 WHIP
250K:98BB. 98 ERA+. 2.55 K:BB ratio
Okay, we can also see that his FIP (4.03) and his xFIP (3.96) is right in line with his ERA for the year, so there aren't any unwelcome surprises. And if you look at his 2012 season, where he had a 5.09 ERA, his FIP (3.81) and xFIP (3.87) far outperformed what you could reasonably expect. Over the last two years, he's averaged 2.2 WAR.
Erik Bedard was a 1.5 WAR pitcher, Jordan Lyles was a 0.8 WAR pitcher - so just right there, you can see that Feldman is an upgrade, with far better peripherals. Bedard walked 4.43 BB/9 in 2013 - Feldman hasn't had a season with a BB/9 over 3.00 since 2009. Lyles got 5.83 K/9 in 2013 - Feldman got 6.54 K/9. Bedard got a 35.6% groundball rate in 2013 and while Lyles somehow got a 48.5% GB%, Feldman's GB% was 49.6%.
So for an average annual salary of $10m, the Astros added a perfectly average pitcher. And if that's not an upgrade over 2013, I don't know what is.