I used Virgin to travel to London fairly frequently but irregularly.
Invariably I booked an Advance First on an offpeak service, often going out the day before my appointment as the difference in price paid for a London Hotel for the night and I also return in the late evening. Although the main reason is to avoid overcrowded peak services for the reasons below.
My Company's policy is that First Class can be used for all rail journeys over 90 Minutes (provided a meal is not also charged). My usual rail journey is currently 127 minutes and incidentally total travel time will increase with HS2.
Since April this year however a number of my services have switched from 11 coach Pendos to 9 coach Pendos with only 2 coaches of 1st Class (plus the infamous rail staff only half Coach K). The experience was so poor with what is effectively overcrowding in First Class that I now try to avoid all journeys operated by 9 coach Pendos.
Why is first overcrowded at 66% occupancy? On a Pendo the tables are so small that you cannot use a laptop and have an a4 sheet of paper plus a coffee/tea cup on the table if all the seats at the table are occupied (even with someone who is not trying to work), also you are always playing "footsie" with the person opposite. This is particularly bad on the tables for two and the few single seats also do not have a large enough table for the above test. This means that you are not only uncomfortable but you are unable to work on the journey, especially if it the nature of your work is at all confidential.
The food offering is welcome but has consistently degraded over the 22 years of the franchise (I did purchase an on board meal before Virgin took over the Franchise). As I used the cheaper off peak services, I haven't been eligible for the hot meal services for some time, but was generally happy with the snack/bacon roll type offering provided I got at least three tea/coffee services and the bar service was very welcome (provided I wasn't going straight into a meeting).
Because of the 9 coach Pendo issues, I have made my last three journeys by car as I cannot count on doing any work on the journey and the road journey time is less than 30 minutes longer, when you add in time to station plus time to secure a car park space and completion of journey to ultimate destination. The cost by car is a bit more than my supercheap advance tickets plus the cost of start and finish journeys and car parking or taxi fares, but not by much and probably the biggest add on with the road journey is the cost of the meal en route.
I don't think I am alone in my use of the service on this basis.
What do I think of a premium standard offering? It would all depend on the comparative prices but most importantly whether I could be sure of getting the space I need. The key factors to my decision will be the cost versus the road journey alternative and whether I can continue to reserve my particular choice of seat giving me an indication of the likely loading. If Avanti are going to convert 1 coach on the 9 coach Pendos, I will not be using them at all. If they are converting coach G on an 11 coach Pendo I might either use the premium offering or continue to book 1st Class provided it meets a comparison with the car journey costs.