I read good and bad reviews before trying the robo sander, but decided to get one anyway and give it a try. For the price, it does a satisfactory job. I am able to place my riser in the jig, run it along the the drum, and then it is ready to glue up 80% of the time. The twenty percent of the time it doesn't work perfectly, it only needs a couple of touches to get the riser ready. I bought the metal sanding drum when ordering and that may have made a my results different than others. Also, I found your technique makes a big difference, using long light strokes gives me better results than trying to hog the material off.
A good edge sander, modified as others on this site have done, would be my preference. However, I already had the drill press so the robo sander was the most economical choice for me.