@Reyn,
I should again emphasize that this is not
live chess, but rather chess that is played one turn at a time over several weeks, within "x" amount of days allowed per move. Yes, if both players happen to be on at a time, you may get several turns in a row, but most times, that doesn't happen. This is why, it's best to have several games going.
The good thing about this type of chess, is that it allows you to thoroughly study your position and strategy without the time pressure of a live game.
My 2nd choice for a site that plays this type of chess would be chessworld.net.
I wouldn't want to advise what site is best for live chess these days, since I haven't done that for many years.