I am fairly invested into the SF2 format. For a time, it was probably the most widely used sample format in the world, due to the ubiquitous nature of the soundblaster series and the large number of amateur musicians that could afford it. It is not the most professional format, but it is a complex format compared to mod tracker sample formats. Most sf2 converters / playback units don't accurately play back the format. What most sf2 converters support are the sample maps, the tunings inside those maps, and the loop points of those sample. Most converters disregard the volume and filter envelopes, with the filter being more commonly ignored amongst various converters. When you ignore the complex method that the envelopes and filter settings are handled, the rest of the format should be fairly straightforward.
Awave is one of the better converters. It can for example preserve both filter and volume envelopes when saving to some other formats, for example Kurzweil. (.krz)
If someone has a ton of different sample formats and wants to be able to easily convert basic sample maps, awave is certainly a program worth looking into and is worth the price. I believe that Awave can convert an XM into a midi file with an SF2. Those wishing to port tracker work into platforms such as Cubase, Cakewalk, Reason or Logic should find this feature to be a time saver. Obviously, tracking is it's own advanced format and many unique features (if used) will be lost during this conversion. For basic "play this note at this time for this long" the conversion should get the work done.
Speeder: If you send me the SF2 I will convert it to xm for you with Awave and you can tell us how you feel it has converted.