ESPN's Keith Law (Insider-only) has ranked the Pirates' farm system seventh best in the game, noting that nearly all the Pirates' minor-league teams should have "at least one potential star." The Bucs rank second among NL Central teams, with the Cubs unsurprisingly ranking first overall. The Cardinals rank 13th, with the Reds 17th and the Brewers all the way down at 28th. (Law notes that the Cardinals have plenty of potential complementary players but don't have any star-caliber talent in their system anywhere above rookie ball, while the Reds have a high-beta system that could soon take a step forward.)
It's hard to argue with any of that -- to the outsider, it's clear that the Cubs have a fantastic farm system, the Pirates' is very good, the Brewers' is terrible (although last year's draft should help), and the Cardinals' and Reds' are somewhere in the middle. The Pirates, of course, have plenty of high-profile talent en route, with Jameson Taillon, Nick Kingham and possibly Josh Bell set to arrive at some point in 2015, Tyler Glasnow coming in 2016, and a ton of interesting talent in the low minors.