MTK MT6575 CPU + 512MB generic 4.3" to 5" size phones from China

Anyone have one of these? Caveats? Battery life? The ones I'm looking at are surprisingly affordable, for the spec, if you can live without HSPA+ radios. Cost is kept down by using 800x480 screens, and they typically have only 2GB or 4GB of storage, the rest of the storage is added by microSDHC card. I'm looking at models in the sub $200 range.