There are no anti-aliasing settings with Maxwell as who would want a non-antialised image that was supposed to look photoreal? No one.
So it's always in an equivalent of "full anti-aliasing mode" if you will.
Unlike LW, Maxwell works like photography. As with a real camera, you achieve crispness by setting the focal distance correctly, the lighting, the f-stop, etc. If your object is .5 meter from the camera and your focus is set for 30meters, there's a pretty good chance the object is going to look out of focus in your render just like in reality. So change your focus in that case to .5 meters for a start. There are other things that affect it too. If you know nothing about photography then you'll have a little learning to do I guess, but at least with your license you have access to the docs and the forums to get up to speed.
As far as the object missing parts, what version of the plug-in and Maxwell are you using?