The trains were usually punctual and I never missed a connection.
The tickets were not exorbitantly expensive, though I saved a lot by booking ahead.
The staff were courteous and friendly, like the wonderful man steering his refreshment trolley through the narrow aisles hawking his fare of "snake-venom and squirrels on sticks".
I almost always got a seat.
The trains between Swindon and Bath have free wi-fi. Cardiff buses have it, too, now!
However, the trains were mostly old and worn-looking.
Some trains just weren't big enough - for example between Cardiff and Swansea there's a half-hourly service, but the train has just two carriages and the ones I was on were absolutely jam full of people.
Some of the stations are looking scruffy, too.