I last flew VS Upper Class in 2009, so my opinion might not be as relevant now.
In general, a good seat if you don't mind the herringbone arrangement (better if you are of the right "size", i.e. not plump).
Food is pretty boring and, if you ask me, not good at all. But there are a number of reviews out there that say that the food is quite good if not better than satisfactory.
Try the inflight bar - if only for the shiggles and possibly chatting with a few other pax (keep the noise down if it's sleeping time, though).
Amenity kits are pretty basic - just a shoe bag which you will fill with other items taken from a basket.
If you have a chance to use the Clubhouse in LHR T3 (i.e. on the way back), you'll find it's probably one of the best, if not
the best, Business Class level lounge in the world, and hot on the heels of some First Class level lounges (well, mostly referring to the USA based airlines who don't know style and service if it hit them on the head). If you are arriving into LHR, you'll have access to The Arrivals lounge provided by VS.
If you've booked your Upper Class service in cash, you should be entitled to limo service on both ends of the journey. If unsure, call Virgin Atlantic and confirm this, then book as necessary.
An album of photos from my Upper Class experience is found here:
FlyerTalk Photo Albums :: VS Upper Class and The Clubhouse LHR T3: LHR-HKG
As I said, these photos are from my experience in Dec 2009. The flight was LHR-HKG, leaving LHR about 2140 and arriving HKG 1700.