XTZ 93.22 - $440/pr (93.22 and 93.21 use same drivers/crossover, just different cabinets/tuning)
Arx A1rx-c - $350/pr + shipping
Having owned and enjoyed the NHT Absolute Zero, I think both of these are more capable speakers for the money. I think the XTZ sound very good, are reasonably easy to drive for bookshelves, they are built like tanks, and have a nice gloss black finish. I had the Arx A1b, the predecessor to the A1rx-c, and they were solidly built with very good sound quality. The downside was the less than stellar looks and low sensitivity.
I haven't heard the others, although I have heard the Aperion Verus Forte center, and was a bit underwhelmed. Unless specifically looking for small speakers, the Forte satellites would not be on my list of $500 speakers... and even then, I'd recommend the NHT Absolute Zero instead. If smaller was necessary, then I'd probably recommend the SVS Prime Satellites - they measure better that the Verus Forte and cost less (although with a bit less bass extension).
I would like to hear the SVS Prime Bookshelf speakers...