There is a free alternative that works very well. It is called AVStoDVD and can be found here: http://www.videohelp.com/tools/AVStoDVD
The HC encoder included with AVStoDVD is as good as many mpeg2 encoders that cost hundreds of dollars. I would prefer it to ConvertXtoDVD personally, but it has been years since I last tested ConvertX. Maybe it has improved.
ConvertX is probably more versatile in menu creation, since that part of AVStoDVD is fairly rudimentary.