I'm riding an Amtrak for the first time, on the line from Pittsburgh to Manhattan. I agree with much of Sausage's review from forever ago, but I'd like to go into a bit more detail.
By car, this route takes me about 6 hours. The train takes 10 hours, and I only get a choice of one train per day, so I have to accept that schedule. Unlike Greyhound buses, there are no overnight options, so traveling this way will consume an entire day each way.
Amtrak is faster than Greyhound, but not by much.
The "dining" car is nice. Instead of seat rows, there are restaurant-style booths with tables. The tables are big enough to spread out some papers if you need to do any work. In the middle of the car is a cramped bar-like area where you order food from a guy who doesn't seem very happy to be alive.
The food is better than airline food, but the sandwich I got (chicken something) was pretty bad. The chicken was very gummy, and I think the rubber slab on top was supposed to be cheese. The whole thing was microwaved in its little pouch, making the bun soggy too. This masterpiece was only the size of a McDonald's hamburger - hardly worth $5.50.
The coffee is decent, and the 12-oz. bottled water is just like every other bottle of water, but I'm not very enthusiastic to pay $2.00 for each of them.
I recommend bringing your own food if you can.
I have a ridiculously large amount of legroom, and next to many seats are standard AC outlets. Good move! Now we don't need to stretch our laptops' 2-hour batteries to last for 10-hour rides.
The seat-backs have trays like airplanes, but the horizontal arm sections can expand to an impressive range to span the large legroom and reach you. They're a bit too high for comfortable typing on a laptop, but they're great for watching DVDs.
The seats are slightly wider than airline seats and arranged in pairs, but there's no center armrest, and the side armrests are too short with knobs protruding out of them. This design is excellent for passengers with no arms.
My train is very bumpy at times, mostly around Philadelphia - often too bumpy to use my laptop. Overall, the ride is worse than a plane, but better than a Miata on a Pennsylvania highway.
This probably isn't a testament to Amtrak's success, but the train has been mostly empty for significant portions of the trip, letting almost everyone have two seats to themselves. Even when it's full, the seats are big enough that you don't squish against the person next to you unless at least one of you is very large.
The bathroom is like a very big Greyhound bus bathroom, complete with the awful smell and gross metal toilet. There's a real sink with running water, not just some packets of moist towelettes. Unfortunately, it has the annoying faucet handles that need to be held constantly to keep water flowing.
I'm sitting a fair distance from the bathroom, but the smell still reached me when every passenger on the train decided to take sequential dumps in my car's bathroom at around 4:00.
My round-trip fare was $108. If gas costs $3 per gallon and I drive this route in a Prius in heavy winds (45 MPG), the round trip would cost about $50. But in most average sedans of average ages (26 MPG), it would be $85.
Unless you have a very efficient car, driving isn't a very significant cost savings. But driving gets you there almost twice as quickly with the freedom to choose your own schedule.
Given the choice of Amtrak or Greyhound, I'll gladly choose Amtrak. The price isn't much higher, and it's far more comfortable.
But if I had a reasonably efficient car, I'd rather drive. Sure, I couldn't play around on my laptop, but for most of this trip, I've amused myself in the same way I would while driving: audiobooks.
It's nice to have the option to fall asleep, but with trains running throughout the day instead of overnight, sleeping isn't a very attractive option anyway.
It would be wonderful for trains to replace short-distance air travel. But with the limited schedules, low station availability, and long travel times, I don't see that happening anytime soon.
Amtrak is a great choice if you don't want to buy an expensive plane ticket, but only if it goes where you need to go, you can't reasonably drive, and your schedule is flexible.