Oh yeah, I'd say that chip is definitely worth $128. I'm just not too crazy about AMD marketing half-cores as full cores. It just feels kinda...shady to me, I guess, especially since they have a hard time beating a hyperthreaded quad-core part from Intel running at a lower clock speed in both single- and multi-threaded workloads. I'm also very disappointed that AMD didn't learn that deep pipelines are bad news when it comes to CPUs, but at least they seem to be slowly recovering from that (everything after Bulldozer has been a marked improvement).
That said, AMD definitely still has my vote for a good mid-range CPU. It seems to me like the i3 pretty much took over the low-end, as they're usually available for the same price as roughly equivalent AMDs and typically have a performance advantage, but the i5 is still too pricey for mid-range. The i5 feels kind of redundant to me at this point outside of certain special applications (for example, the ULV i5 that they use in the Surface Pro 3 and similar systems is basically the perfect chip; the i3 wastes battery by being too slow and the i7 wastes battery by being too fast...and will burn your hand).
I'll have to start a thread for my mini-ITX build after I nail down some specs. It's mostly going to be a DDR/StepMania system, so I'm aiming to build something relatively cheap. Probably just going to stick with an i3 with Intel graphics running Gentoo. I was initially investigating a low-end AMD APU, but from what I've seen and heard, Intel GPUs typically outperform those. Must investigate further!