I recently did LX F on BKK-SIN, and was pleasantly surprised at the more extensive (than SQ) meal offerings on this flight. I took SK J last year (they have since cancelled this tag flight) and it was pathetic--no IFE turned on, no duty free, and a salad as a main course in J--no choice!
So I wasn't expecting much, but here is the menu. Q Shoe Guy, CGK, and Carfield (I think) have all commented on the incomplete meal offerings in SQ F on this route, so I will mention that the "supplementary choices" section was offered to me--I didn't have to request it--and so I ended up with a salad, main dish, cheese course (not on SQ), dessert (it was a chocolate cake, also no dessert on SQ), fruits course, Swiss Chocolates (not on SQ), all the while topped up and offered with Port, Dessert wines, champagne, and finished off with a nice coffee. So, it's really no comparison--in addition, if you don't want any of that, there is a full-flat bed, slippers, eyeshade, AND a full amenity kit--which was a great black BALLY hanging toiletry bag with superb La Prairie products.

LX 182
BKK-SIN
Light Meal

Fresh Seasonal Salad

Green Chicken Curry with steamed rice
Salmon Steak served with lime butter, asparagus, red bell peppers, and saffron potatoes

Sweet favorites

Swiss Chocolates

Espresso and a selection of coffees and teas

Supplementary Choices available at your request:
Selection of soups (cream of tomato, oxtail clear, Miso)
Seasonal Salads
Swiss Cheeses
Fresh Fruits

Now, I will await the SQ fans' excuses as to why LX doesn't need to offer such extravagances, etc... and that SQ's offerings are enough--but still, if you're looking for an upgraded F class experience, LX's BKK-SIN is available.
And I DO love SQ!!! I flew on SQ the next day, new F, SIN-ICN, and it was fabulous!