HST, namely FGW ones. First reason being they're HSTs, second they're amazingly comfortable and offer more legroom than any other UK trains.
Class 91s i've not travelled on so much although i have no problem with them, ditto class 373s. Class 390s i have serious problems with. They may look nice and modern but internally they are rattly, uncomfortable, cramped, claustrophobic and smelly. Also they make me feel a bit sea sick when tilting. The Class 180s are about the best DMUs around for travelling in, and i'm looking forward to trying a Class 395 shortly.
Class 91s i've not travelled on so much although i have no problem with them, ditto class 373s. Class 390s i have serious problems with. They may look nice and modern but internally they are rattly, uncomfortable, cramped, claustrophobic and smelly. Also they make me feel a bit sea sick when tilting. The Class 180s are about the best DMUs around for travelling in, and i'm looking forward to trying a Class 395 shortly.