Um, thats not what the speed settings on Motorola phones does. The setting affects how often the phone searches for a signal when in a no signal area. For example, if you are underground in the subway, you might have no reception. However, the phone is constantly looking for towers to connect to. The speed setting affects how often the phone searches for those towers. The fast or continuous setting will search more often, giving you signal sooner once you step back into an area with signal, but will drain the battery faster. This does NOT affect reception, and will not give you any better reception.
SE phones generally have very good reception, but it does depend on the model. Some, like the W600i, W300i, the Z710i are excellent, while others like the K550i may have issues. Motorola is also quite good, but again, it depends on the model.