To answer a previous question, no you don't need a cell phone. I believe there are USB readers that will work with Forscan on a laptop.
My personal preference is go with a Bluetooth reader for greatest flexibility and convenience.
I have seen many people complain about issues related to setting up and maintaining connectivity with the WiFi readers. Some models probably work better than other, but I would research a specific model for issues before buying a WiFi reader.
As for going with the cheap $20 readers, the common issue with them is that they can't read the higher CAN BUS speeds reliably. In many cases, they may 'read' values at the higher speeds, but crap out when sending a command.
Given the universal value of a good OBDII reader across all vehicles, I would probably stick with a brand name reader that has some level of quality and customer service. A good OBDII reader with Forscan can save hours off your diagnostic time when troubleshooting. When my trans was slipping badly, the system told me exactly which shift solenoid was the problem. Without that extended code telling me which shift solenoid to replace, I would have never figured it out myself. I even tried 'testing' the old solenoid, but it gave good induction values. Nevertheless, replacement of the solenoid solved all my problems instantly.
