jebr

Except that it's not so quick to get out of Clinton, especially with luggage. I don't think there's an escalator all the way up to street level, so there's a flight of stairs up. That's not bad if you're able bodied, especially without significant luggage, but if I have a couple bags that's not pleasant, nor is the two-to-three block walk on sidewalks not optimized for luggage. It's plenty doable, but I'd much rather do the Metra if the schedule allows.

If the OP was simply going to the Loop, then the Blue Line is better as it likely gets closer to the destination. But since the OP is going directly to Union Station, Metra is easier if the schedule allows. Sure, there's more transfers, but they're mainly substituting for longer walks: ATS vs. the walk to the Blue Line station (which is pretty long from Terminals 1 and 3, and would require an ATS ride anyways from the international terminal) and the shuttle bus vs. the stair climb and 2-3 block walk at Clinton. The fact that it drops you off right at Union Station is also a huge bonus; while the walk isn't difficult from the Blue Line, you still have to get your bearings and there's a chance that you get turned around and add a couple blocks to your walk. That's quite unlikely with the Metra connection.

The couple times I've been lucky enough to take the Metra connection, I've found it a lot more relaxing and a lot less stressful. If the schedule works, I'll pay the extra to use it because it's just a much better experience.