I have the DeWalt and it has worked flawlessly when I've needed it. One thing I've used it for that is handy, is to make spline slots on the ends of longer material that would be more difficult to handle on other machines, and also quicker, (and safer) than setting up and using other machines on certain short pieces. On this type work, I just clamp the material to be slotted to a bench and run the BJ's fence up so it is not in the way and set the BJ's base flat on the table and make a series of slots, (Very quick and accurate). If, however, you are have a need to use the real small biscuits, (like for picture frames, etc), then you probably need the PC 557, because the DeWalt will not cut those, but I never had the need for that application.
I don't use it often, but it sure is handy when needed.