Whelen is a good brand and their sirens are very reliable... when they work correctly (435Hz ones malfunction sometimes; I'm thinking about contacting the people who deal with the ones here in Muscogee County and asking them about upgrading the controllers, not that they fail or anything, but because it can happen and has happened to others
like this one). Their 560Hz controllers are great. To me Whelen and Hormman make the best electronic siren controllers (FS over-pitches the UV controller stock, and so far I haven’t seen many in the US that are programed otherwise; ACA/ASC over-pitches their controllers too; ATI=POS

)
But here's the big picture:
Electronic sirens, any brand, are not always the best though, and you can sum it up with these equations:
ATI=you know where this is about to go
Unwanted electricty (static/indirect lightning)=Siren goes poof
Controller fail=hole in somebody's pocket :thdown:
Some overdramatic EMA goes:

"let's replace the whole system" (A bigger hole in that pocket, although replacing anything ATI is money well spent)
With that being said, I can understand why some people dislike electronic sirens.
An AC mechanical siren and a good controller won’t fail as often and isn’t as expensive to fix. DC mechanical sirens are good, but not the best.