As always, it depends on YOUR requirements.
If all you want to do is connect an Obi to WiFi with minimal fuss, then ObiWiFi makes a lot of sense.
But if you want to connect some other items along with the Obi or don't have good WiFi access, then a WiFi bridge or Powerline networking can make sense.
In my case, I have the Obi 202 and another WiFi AP together, so PL networking made sense - and the Powerline adapters were pretty cheap.
I have also converted an older router to a bridge using DD-WRT (to get wired access from a MiFi), and the whole process was pretty simple.