definitely going to depend on the position, it is also a lot harder to fork in the endgame because there's much space making the forks much easier to detect. Materially, 2 knights are worth 6 and 1 rook is worth 5, so about a pawn difference in favor of the knights. however, a bad thing about knights in the end game they're often left with a 1-dimensional use (defending a and/or pawn(s)) but if you have the pair of knights together defending each other and in a dynamic attack position with the ability to push pawns along you'll find it very favorable. So to answer your question, against a weaker player<1400 i'd take the rook to propose sharp tactical play, against a stronger opponent i'd take the knights for the strategic positional play.
endgame 2knights versus rook

it all depends. you can never mate with two knights, but you can with a rook. However, if there are pawns on the board, it gets more complex.

if there are no pawns on the board, then I 'd ahve to go with the rook because you can checkmate. But to be honest I think that position is drawn if both sides play well.

Well Santir and Sebas, a rook against two minor pieces is usually a draw.
For pawns on the board, we can look at the table provided by Wikipedia:
* The two pieces have one or more extra pawns: always a win for the pieces.
* Same number of pawns: usually a draw but the two pieces win more often than the rook.
* The rook has one extra pawn: usually a draw but either side may have winning chances, depending on positional factors.
* The rook has two additional pawns: normally a win for the rook (Fine & Benko 2003:449-58).
Hi I was wondering if a rook is better than 2knights or if 2knights are better than a rook in the endgame.