@An ******
I have travelled that route in all three classes and yes business class is much better than the other two. Traveling so much I can use upgrades. The difference ( in my opinion ) between premium economy and regular economy is quite minimal. A slightly larger seat and a few inches extra legroom.
The big difference is the cost. The difference between business and economy is in the region of $2500. The difference can buy you 18 nights at the Hilton on Sukhumvit in two room suite, including breakfast, afternoon tea, evening drinks and appetizers.......la difference and your choice.
You can check out all the seat charts at seatguru.com