Superficies is from a legal point of view recommended if the (leased) land is undeveloped and you plan to build on land you do not own. Legally the land lessee is better protected when his land lease is combined with a right of superficies.
Note: the land offices in Thailand are often unfamiliar with the structure land lease and superficies and it is not guaranteed that they will accept registration of both a land lease and right of superficies. They should accept this combination as there is legally no objection against it and it is a common structure in other civil law countries.
This superficies (7 pages) is a lawyer drafted contract to be used in combination with a land lease agreement.