Steve nailed it... as pretty as the ULS interface appears at first glance, it's not nearly as user-friendly as it could be. Somewhere around here I keep a list of my annoyances with the GUI, but I could recreate most of that list without too much trouble just because the things really annoy me!
Being able to modify the dpi in both axes independently makes for a more powerful machine, but I see no valid reason for not giving me full control. Don't allow me to type in a value between 1-1000 in one axis, and then limit me to six pre-determined values in the other. If you must limit me, then don't make it a slider with symbols that have no direct bearing on the setting, and certainly don't display symbols that don't follow the nomenclature you set up for the other axis! Both axes use stepper motors of the same type, so there's no need to limit me to those six values... by doing so, you usually limit the values that can be chosen for the other axis, as well, diluting the capabilities. If people (e.g., beginners) often choose the same value for both axes, have a checkbox that locks the two axes to the values selected from a single slider or entry box. It's not friggin' rocket science!
Just once I would love a ULS rep to say to me "We understand you have some ideas that may improve our user interface, and we would loveto have a look at them." But they won't... because that's how companies operate. Allowing outsiders to make suggestions would make them look weak, like they don't have the proper expertise in house to make a GUI... problem is, it's obvious they don't. You should never design a professional product's interface without using a professional. Yeah, it's better than a DOS command line, but it frustrates the user nonetheless.