I have used plenty Logos and S7-224 and 226 PLC's. Also often S7-300. Personally I think the Logo is more reliable than S7-200 but obviously limited. I would try program the project in Logo software - you can simulate everything without any hardware. If it works - don't give it up as a bad idea. Obviously S7-300 much better but expensive. If you go S7-200, don't touch anything less than a 224.