SPP-C and HC-05 are they the same thing or something else?
In theory they are the same and have the same capabilities. Practically they are not. With SPP-C you get twice the headache for half the price as for HC-05. In had to find it out the hard way Sending data using Bluetooth SPP-C Module without a Breakout-Board. I tried both SPP-C and HC-05 with and without breakout boards finding the same issues. So if you are willing to spend time, risk your project and save some money then use SPP-C. Otherwise use the well known HC-05.