I like my Smidge cup - the screw-on lid is pretty much leak-proof when closed; you can drink through it; and it comes apart for cleaning.
My only issue with it is that the inside is a bit tea-stained, but I think that’s a problem with tea, not the mug.
(They also do nice water bottles)
Of the million other reusable cups we have in the house, I think KeepCup are probably my other fave - I see they’re now doing Chillys-style mugs too.