I like DS9 because the characters are flawed. Sisko isn't some confident paragon like Picard. He starts the series a broken man. Kira was a terrorist, Odo helped out during the occupation, Bashir lied to get in to Starfleet and don't get me started on Garak...
The flaws and different facets are what make these characters so much more interesting than Geordi LaForge, Dr. Crusher or Troi.
Agreed. I only started watching the first season recently, but I do like that they are inherently flawed from the get-go.