Carrier, considering that I pax with First Great Western (FGW) and Virgin Trains (VT) quite a lot, I have to disagree with your assessment that VT is the worst. Sadly, us in the western corridor have to deal with FGW, and they are worse than VT used to be in their bad days (after bringing in the XC diesels and before the Pendolino).
The VT Pendolino services are arguably some of the best services I've had the pleasure of travelling on, certainly bending better than TGV or Eurostar do (both TGV and Eurostar 'bend' based on grading, not actively tilting like the Pendolino does), but worse than a Shinkansen.
When FGW finally gets round to completing its renovation schedule of the MkIII carriages on their HST125's á la GNER while improving service reliability (they are terrible on that), then I might change my mind. The FGW Thames Turbos are in a pittance of a state, and more often than not we are delayed out of Paddington because of some reason or other on the service, not because of signalling (which the Reading-Paddington corridor is infamous for).
Generally, the state of British rail is good. South West Trains (SWT) do a reasonable job, GNER before Sea Containers went bang and they lost the franchise was not bad. Funnily enough, West Anglia Great Northern (WAGN) wasn't too bad either with their fast services. Their local stopping services left much to be desired. And since First took over the franchise for First Capital Connect (FCC), the service has gotten worse.
S.