F is quite good for this route since it is only a 2.5hr flight. I think you will find the cabin to be comfortable depsite the fact it is showing its age. By the time the meal is done you will be there. The last time I took this flight I was able to get a menu faxed to my hotel in BKK and order the meal in advance. You will get Royal First service in BKK also for what it is worth. The limo service was handy as well. Also, they provided golf cart (dont know the name) service in HKG once you got off the plane to immigration which was handy.

I have been taking the EK flight in C/J lately but still TG has good service on this route despite the older aircraft and seat configuration