 If you liked
Kiseijuu
|
 ...then you might like
Tanabata no Kuni
|
If you preferred Tanabata no Kuni then by all means proceed and read Parasyte, which is Hitoshi's praised work -- also contains SF / Horror elements.
Vice versa -- Tanabata no Kuni is basically a copy of Parasyte. Not one of those shameful copies, but similar in many traits, albeit certainly fun to read.