The AMD 990FX is a bit of a toss-up for most people, but it has key benefits for certain enthusiast users. Normally, new chipset launches are absolutely dependent on a CPU launch to fully see any adoption, but the 990FX provides that backwards compatibility to make the case for a potential clear upgrade path.
If you are an existing AMD Phenom II user, already committed to buying into Bulldozer, and absolutely want SLI with the current crop of cards, this is a no-brainer. Keep in mind there won’t be any major GPU launches until the end of the year, so the current generation of SLI-ready cards is going to be around for quite some time.
However, it is kind of a dead-end to non-AM3 owners. Most people will not want to purchase two CPUs in the same calendar year. Essentially, if you are not an existing AMD user (whether doing a major PC overhaul or looking to switch from Intel) you are better off waiting for the CPU to launch, whenever that will be. In any case, you can be assured that the prices will be competitive and provide you with another solid option for your next system build.