I've never got the enthusiasm for ex-BR LHCS. Most of it was decidedly poor compared to its European contemporaries, often with an iffy ride (bounce on Mk2, sway on Mk3, particularly short swing-link versions), poor air conditioning and manual doors as well as absolutely terrible seats.
My enthusiasm for Mk 2s and Mk 3s is because I consider those points to be either false or beneficial (ignoring the bit about "European contemporaries" because I've never been on any).
Never found anything to complain about in the ride of either Mk 2s or Mk 3s - yes the latter did sway a bit, but it was never objectionable, and they were vastly better than a contemporary DMU.
Nor did I notice anything wrong with the air conditioning apart from its mere presence once it arrived; the early Mk 2s were preferable because they did not have it.
Manual doors are a definite point in their favour. Sliding doors may be supposed to look all Star Trek, but they don't behave like Star Trek - Kirk can stride through the doors at normal speed without checking his pace because the doors move quickly and get out of his way; he doesn't have to wait for a button to become pressable and then wait for it to register that it has been pressed and then wait for a geriatric hamster to stagger round its wheel to operate the mechanism without even the benefit of any amphetamine in its water bottle. The machine should be the servant, not the master.
Seats are excellent. Particularly on the Mk 2s which have the best seats for a 2+2 open ever, and all perfectly aligned with the nice big windows too.
And as well as all that, they were usually provided in rakes of decent length. It took a while for the rot that set in with the HSTs to become general. Outside of busy periods where overcrowding was inevitable, it was much easier to choose a decent seat not too close to other passengers, and the general ambience was much less oppressive.
I just find sitting bolt upright on the 730's very very uncomfortable!
Seat designers ought to throw away those nice neat diagrams they are so fond of which show silhouettes of human forms sitting militarily to attention in outlines of train seats, and instead pin up on their walls photos of real people sitting in a real row of seats, one which doesn't have another row of seats directly in front of it. Perhaps then they might get the idea not to design seats that are only comfortable if you're an Action Man with no legs.
) so it was pretty grim unless I got a table with nobody opposite. The refurbs with different seats were generally better in my eyes, but then some of them ruined the lighting (which was too bright to start with) so I didn't really find any perfect.