I do like the first class seating on the FGW HSTs, however when I travelled on the Swansea to Paddington service I didn't find the service as good as on NXEC or EMT - the person didn't seem to come around as frequently. I did however like the offering of crisps in the snack selection.
I also prefer my tea or coffee in a proper mug rather than a paper cup. However saying that, NXEC occasionally have issues getting their mugs fully clean.
Another thing, which is rather niggly was that I found the power sockets to be too close to the table top, so when I was plugging my laptop in I struggled to manage it as there wasn't enough space for the cable coming out of the bottom.
Additionally, wifi would be a great addition to the service as quite a few people I noticed had laptops tethered to their phones or dongles, but the 3G coverage along the line isn't that great.
Of the 3 intercity TOCs I've experienced, I'd say FGW are very good, but I found the service with EMT to be slightly better. However that could be as when I've travelled with them I've always been in the carriage with the kitchen.