When I rented this show from Blockbuster years ago, it looked very pretty, but animation has advanced a lot since then. Now it seems so hand-painted, it hurts. Nonetheless, the art has a certain charm to it.
A few more issues are present. The background story takes a toll on my ability to suspend disbelief. For example, if Hikaru is made out of liquid metal, a-la T-1000, why does she eat, and how does she digest the food? The background music switches to an extremey retarded game music for a battle. Mind control is lame.
Still, the show is a net win thus far. I watch it for the little moments, like cute lip-chewing, or Hikaru being caught eating ice-cream (I thought it was a sour cream at first. A different childhoods we had!).
Update: Steven catalogs varying relationships between androids and the food. When I made the off-hand remark above, I did not bother to think about it, it just seemed strange. Later, Hikaru makes it clear that she is obsessed with re-living Tsubasa's experiences, which she received as part of cloning process. This probably includes eating. A logical extension would include defecation... Mecrifuly, this was left out (for now). She obviously cannot do it all, such as meeting people already dead.
Update: Jonathan comes up with an explanation (see also his review linked there).