SOS 385 remote handheld for several reasons...looks, size, single-side wire exits from amp, good tones, 3x 20 amp outputs for the progressive switches, versus 3x 10 amp for Whelen HHS2200. If Whelen would make the legend stickers and backer plates a better design and make the wires exit the amp unit on only one side then the HHS2200 would be a tie. Worst is FedSig's PA650, as it is prone to failure, has horrible tones, buttons can't be labeled, and you need a u-terminal crimp tool to assemble the connectors.
Carson SC-550. It's the original version that was released by through SVP. So, technically, it was the first hand held siren released in the US market. I brought one new, when they first came out. I still have it. Although,I have to say, I do like the look and feel of the SOS. My own problem with it is it's only 100 watts max. I'm a 200 watts (at least) kinds guy.