I'm very interested in the Spartacus model myself. I'm intrigued to how the changeable nozzles affect the sound. I haven't found that feature in any IEM under $100, so for $12 it's definitely worth a shot.
The E19 I didn't order. The Maya models are good, but they tend to be a little more expensive than most chinese iems. The ones I have are good, but haven't blown me away for the price. The Military model came with awesome accessories though (foam tips, bag, coin, tin), and sound good.
Maya makes other stuff like LCD monitors too, so they are a big company in China.
I'll probably let someone else try the Maya E19 and give their impressions. It looks great, that's for sure.