The Solo II looks like a good improvement on the latest Sonata (III?) case. I like that you don't have to open the door to get at the 5.25" bays and that the door gives access to the filters. Cleaning the filter on my Sonata I is pretty annoying. Of course I'd still take my Antec P183 over the Solo II, but it is much larger and likely more expensive.
IMO, the rest of the cases are ugly, but I prefer the clean looks of Antec and Lian-Li's cases.