My experiences have been different than Marq's ... maybe it's a luck of the draw thing and I've just been lucky, but here is my rundown:
I've done the Portland-Seattle (and one time Portland-Vancouver BC) round trip many times. King St station in Seattle is located about 3 blocks from Safeco, so it's great to go up for a day game from pdx. Or from King St you can take the Sounder (commuter train) up to Pikes Market/downtown area, and from there you can take the monorail (for an antiquated 60s sci-fi kind of experience) to Seattle Center, where the EMP lives.
The trains are almost always on time, at least in my experience. In fact, they don't wait for you, so you'd better be aboard at the scheduled time because it's usually starting to roll then.
Last year I did the Baltimore to Boston (Back Bay sta) round trip, and it was 7 hours door to door (my apt was in downtown B'more last year so real close to Penn Station - yet another Penn Sta!). Back Bay is located only about 8 blocks from Fenway. Location close to MLB parks is a big plus for me. And 7 hours ... much better than driving the NE corridor (by a long shot) and in my book better than flying (I checked and it would have taken me at least 5 hours to drive to BWI, park, shuttle to the terminal, go through security, fly to Logan, taxi or rental car into downtown Boston through that crazy tunnel thing they've got there out of the airport). Saves a lot of aggravation. No traffic to wade through behind the wheel. And, unlike the sardine cans that airplanes have become, train seats are big and roomy and you can walk to the dining car or just stretch your legs, no problem. And you see cool parts of the countryside (and the "innards" of cities", a real graffiti tour) that you don't see from the interstate. Going to Seattle exposes you to parts of the Puget Sound you'd otherwise only see by boat.
Anyway, when I can, I take the train. It's so much better than driving or flying.