I've always been an advocate of using standard class over first class in order to save money.
However, for me the main advantage of first class is greater availability of advance tickets.
For example, if I want to travel from Liverpool Lime Street on Monday morning, I can buy a £12 advance single, but the earliest train I can get is the 07:34 from LIV which doesn't get me there until 09:18 - which is later than I require.
However, for just £7 more, I can buy a 1st class adv single and take the 06:30 from Lime Street which gets me there at 08:17, which is more useful to me. There are no standard adv tickets available on that earlier service.
So for just £7 more I can take an earlier train. Plus of course, 1st class will be very quiet and probably more relaxing than standard.
So, lately I've started to warm to 1st class for the simple reason that it makes more trains available to me at a reasonable cost (strictly advance tickets or special offer day rovers only though!)
Complimentary food/drinks is a non-issue for me as I always bring my own food and drinks.