I have bought cheaper versions in the past, and I am glad I went for one that was a little bit more expensive, but worth it.  It slides up and down so easily, not having to hold arms out and getting tangled.  The height can vary, if you are a smaller person.  It folds up and ties so easily, the ease with which you can slide it up and select the height you want is fantastic.  The cover that keeps it clean and dry is perfect.  Opens where you can put it easily around the top, and a zip up from top to bottom.  Perfect, and easy.  Used to have to stand on a chair and try and get the cover over the top with great difficulty.  Wonderful purchase!