If it is between those two, Chessup2 by far.
SquareOff is not a "trusted echess" brand at all.
Also look at Chessnut. The Air is a nice board, a little smaller than a Chessup2 but still very usable.
Chessup2 is a little larger but is still working out some software issues. Still a very good board.
I was looking at echess boards since I like physical chess board but it is so hard to find someone at my level. The two best ones I found were ChessUp 2 and Square Off. These two seem like the biggest and most trusted echess and I would like to know which one would you consider better