Greetings Von, I don't know anything about the "Paint-mate", but I'm guessing that it's one of those items that is designed to sell to consumers to supposedly make painting easier? Trash it because you can get better results by using a regular roller, with a lamb-skin cover over your roller. It will hold more paint, release quicker and leave a much better finish, WITHOUT leaving that freakin' fuzz in your finish. I'd go with either a 1/2" to a 3/4" nap.
As for Ace brand interior latex, if it's the cheap Ace brand paint, I'd do like Steve said and get rid of it. BUT, if it's the "Ace Royal" brand, then I'd stick with it. I've used this many, many times and have been ecstatic with the results it's produced for me. It has the consistency of Sherwin Williams' ProMar200, and the ability to 'block-out' the former color much like that of Sherwin Williams' SuperPaint, which is one of the best. In other words, it's good paint.