I have both SEEP and PECO on my layout and have used both for many years.
You CANNOT rely on the built in switch on the SEEP motors, not only is it cheap and cheerful it needs precision extreme accuracy in positioning the motor. I bought my SEEPs on precisely the same basis that you were thinking and was deeply disappointed. On my previous layout I had no end of difficulty installing them as they need very precise positioning even if you are not using the switch. On my latest layout I am using much smaller boards that could be wired up on a bench where I could reach both sides easily. I was also using ply. In these circumstances the SEEP were much easier to instal. Once installed and working they seem very reliable but then so are PECO.
BEFORE deciding on a DCC system try them out because in my view at the end of the day the choice comes down to the man machine interface and whether you like knobs, buttons, slides or wheels. Several suppliers have layouts set up where you can try several systems together. I personally use the NCE system.