The Orioles traded cash for Jai Miller from Oakland, and moved Brandon Snyder to Texas for cash. Since we don't (and won't) know the actual cash considerations, we will just compare Jai Miller to Brandon Snyder and see if the player they acquired is better than the one they got rid of (i.e. is Miller better than Snyder).
Miller has played in just 28 MLB games, so it doesn't seem wise to take anything from that. He has played in 423 AAA games, so it does make a lot of sense to look at those statistics. Defensively, he is under average, as his outfield range factor shows. Offensively, he has a .351 OBP, 867 OPS, 1.5 PPG, 2.36 PAPP, which is a 2.42 Simple WAR. This projects to be a .93 Simple WAR with an OBP of .305.
Snyder has just 16 games played in the MLB, so like Miller, we will rely on his minor league numbers. Defensively, he is under average at first base. Offensively at AAA (285 games), he has a .317 OBP, .711 OBP, 1.11 PPG, and 3.05 PAPP. This adds up to a -.43 Simple WAR. So Snyder is a below replacement AAA player.
This makes it quite obvious that the Orioles acquired the better player and dumped the worse one. Assuming the cash considerations were about the same, then it appears that the Orioles made a pretty decent roster move.