I tried the emulsion sheet ONCE and decided it was more trouble (and expense!) than it was worth. I picked up the Emulsion kit from Dick Blick and will never go back to the sheets.
You can get the scoop coater, but you can also just use your plastic squeegie/spreader that came with the yudu. That's what I've been using and have had zero issues. (Although - it does take a try or two to know how thick/thin to have the emulsion on the screen.)
And while I'm not sure this is related or not - the images I'm able to get with the liquid emulsion have been really sharp!)