I've got a later version but considered the 12000 series, a few things:
They're very capable for the price especially for high frequency output.
There is little to know service information available (just datasheet and manual) and Gigatronics seems to remove all mentions of previous models from their website.
It's also very difficult to find software for them, though user manuals do contain a GPIB command reference.
At least with my series, frequency sweep and mechanical attenuators are optional - so you may end up with an instrument you can't automatically sweep with to make frequency response plots with a SA's max hold mode and that can't output below -20dBm or so, which are often standard features of other RF sig gens.
If you're looking for high bandwidth alternatives, sometimes Anritsu synthesizers come up with some bandwidth, and while they command a price premium, Rohde & Schwarz makes some very good ones as well.