I'm really enjoying both, for a similar but different sound. I can say that I don't enjoy the BA200 very much unless amped. I find I usually listen to new headphones when I first get them. After a few weeks of listening, I start settling into a favorite, so we'll see what that is. I really enjoy the blues and the IE800's make guitars sound awesome. I will definitely be open to trying TDK products in the future. I guess I always thought of TDK as a throwaway brand or a brand that made cassettes back in the day.
Since they're a large producer of electronics, it seems their product inventory goes through a more generic cycle of progressive discounts. People are finding both pairs of these IEMs at electronics places in the states for obscenely cheap prices that seem to violate basic economics, or at least the model all other IEM companies seem to use.
I really like them for the mid-range focus and am going to give the BA200 a more thorough listen soon. I find the IE800's work well with some genres, but anything that benefits from heavier bass they tend to struggle.