Top 4
GNER - Excellent service, clean rolling stock
Merseyrail - Trains always turn up on time, Merseyside Daysave is a bargain, clean and efficient service. Just a shame they had to put those god awful high backed seats on the 508's but for the short journeys you cannot fault them.
Midland Mainline - Just as good as GNER but the 222's just take them down a peg although for plastic they are pretty good.
Scotrail - Used them loads of times and never once had a problem, its about the only First company which does anything properly.
Bottom 4
Central Trains - Can they go one single day without some sort of disaster?. Service cannot be trusted.
"one" - Again, just a very unreliable service. Worse then Central Trains simply because everytime there are replacement buses the journey becomes an ordeal because your seats are never reserved, the buses are always too early or too late and there are never any staff around.
Virgin - Might just be me but never had a pleasent journey. Both types of new trains are simply horrid inside.
First Capital Connect - FGW can blame the DfT for some of its problems but FCC can blame noone for what has to be the most appauling excuse for a train service. Trains are often filthy inside, reliabilty is woeful, ethics make Belizibub look almost cheerful and for Gods sake don't work for them.