Whelen has improved their sirens a LOT over the past 10 years. The orange drivers and the 2030 logic board were the two biggest improvements. They are fairly reliable sirens, but the older ones are prone to their quirks (2020 board) and the rotator can be somewhat fragile, especially the belt drive models.
They are loud, and the Whelen radio setup works pretty good too. They finally introduced an improved solar charge controller and upgraded the solar panels from 40 watts to 80 which greatly improved battery life.
The best thing is Whelen has an awesome service department. They can repair the majority of the components on the siren, and they don't charge much either.
The ones I service/maintain really don't give that much trouble. We've had logic board issues which were corrected by sending the board back to whelen for a firmware update and the occasional oscillator board failure, and a radio that needed retuning. Other than that they really haven't gave us any trouble.