I've always had good experienced with
32Red. Same goes for Unibet. Not sure if they are connected, but their websites are basically a carbon copy of one another.
I think it's just the luck of the draw. I had a terrible experience with Betfair once and last year I was dragged through endless verification requests from an apparently "established" brand. It took over 4 months and dozens of document submissions ("it's cropped", even though it wasn't; "it's blurry", even though it was crystal clear), and yet they had mostly good reviews.
I recently saw a review on either Ask Gamblers or Coinbuzz that basically said all casinos
can make life difficult for you and if you play long enough, they probably
will. You just have to be patient with them, don't give them any valid reason to suspend your account or delay your payment, and then go through complaints/mediation as soon as they fail to respond through the normal process.