I'd had a few different alarms before buying my Delk's and I can honestly say that they are vastly superior.
The build quality and functions set them apart, that said, some other manufacturers are catching up fast, but that's the ting - they are playing catchup with Delkim, not leading themselves.
They are also VERY easy to use, and just carry on working, whatever the weather or situation.
I would not go to anything else now (unless they offered something revolutionary).
So, are Delk's worth the $, yes I think they are.
£500 for 3 TXI+ and the wireless RX+ Pro reciever (the top of the range, all singing, all dancing etc), which is price comparable to the top models from Fox, Nash etc, but superior in what you get.
I recently bought the TFG Glimmer set for my father-in-law (b-day pressie), which offers excellent VFM at £150 (3 alarms and a wireless receiver) but is not a patch on the Delk's. But they suit his needs better.
We all need slightly different things from our tackle.
I coped fine for several years with very basic alarms, and if you need something to alert you to a screaming take any alarm with do, but as your fishing advances you're likely to need something that is more reliable and offers more features...
While not strictly on topic, please ensure ANY alarm you buy has volume control (or can be muted) so you can set the bobbin without alerting everyone else on the lake. Sorry. This is something that really winds me up...