Ikea beds: what makes Tarva better than Fjellse?

Both are very cheap but Fjellse is half the price of Tarva in my country (U.S.). What makes that the case?

I’m asking because I definitely want a bed frame of that type (untreated solid pine with footboard lower than mattress and headboard higher than mattress), and price isn’t my concern but headboard height is (Fjellse’s is exactly perfect height and Tarva’s is too tall).

Assume I would get the best slats available. My bed size is full/double.