Which covers do you think work best with flats?

I am asking this partly for myself, and partly for my niece who is about to have her first bub, and I'm buying her a stash of covers to use with her flats.

I am VERY happy with my Motherease Rikki covers, and loved eenees snibs when he was a nb. I am less than impressed with my Bummis SWW, am trying to keep going with it, but I'm about to give up. Am changing to terry from flannellette tomorrow, so maybe that will make a difference.

I will get Jess a few Motherease and snibs, but I am also looking at the Thirsties PUL and BBH PUL. Any feedback on either of these would be great, or recommendations for any others.

TIA