Yes, only a couple of frequency's available from this guy. I think it depends what your actual use is. In my case, I use it as a reference to challenge my audio measurement system (pc with good qualitiy sound card). By having an ultra low distorsion generator I can check how much distorsion in introduced by the measumenet system itself (at a single frequency of course...)
If you want many frequencys and DIY, I would built a good quality DAC board with optical digital input and power this board from an isolated power supply. Test signals I would generate with one of the many audio measurement softwares available for free (I presume you pc has a digital out, otherwise you will need an additional sound card).
If you want an analyzer also, just build an ADC board the same way. By using the optical digital out/in and isolated power supplies (seperate power supply for DAC and ADC), you avoid ground loop issues when connecting to the DUT. Don't forget to install some input protection on the ADC if you want to test amplifiers also.
For an isolator power supply, these look like a very good deal:
http://www.mouser.be/new/murata/murata-ps-nxe1/