I have an a6-5200 (which I'm using to write this), and the performance is much better than the machine I replaced (E-450).
The E-450 was too slow. You couldn't want Netflix in HD, for example. It was much less responsive on some web pages too.
The main difference in setup is that this computer is using Windows 8.1, not the significantly slower Windows 7. Yes, Windows 8.1 is obnoxious, and you shouldn't have to work around the idiotic tablet interface. But, it's also a better OS under the absurd interface, and significantly faster. It's also cheaper ($110 for retail version, versus around $300 Windows 7 retail).
I just set up this computer a week ago, and there's just no way I can go back to the E-450, even with preferring Windows 7. The speed difference is too dramatic.
I wouldn't touch this A4 5000 though. Why suffer with 1.5 GHz when you can get 2 GHz? On top of that, the fan barely ever goes on with the A6 5200.
I do recommend the Kabini, and really like this machine a lot (fast enough, very low power, completely silent, tiny, attractive, etc...), but not in the A4-5000 version.
One caveat, be really careful about the memory you buy. I got some 8 GB DDR3 1600 at 1.35v CL8, and the motherboard (ECS KBN-I) can't use it unless I populate the other slot with memory (I had some 1333 memory laying around, but that certainly doesn't help the performance). So, make sure you check their site before you buy it, instead of a being a bone-head like I was and assuming it would work with quality memory.