I have had and used Delkims,Fox,Ron Thomson,Nevs and some cheap Shakespear alarms.I now use Fox STR's which,up to now,seem bullit proof.Delks,although good alarms,are way too expensive.I had the TXI plus and wasn't too impressed with them.Nevs are probably the best alarm on the market,simple,reliable and stong.The only thing that lets them down is the fact they don't do a receiver and transmitter set.You can however buy the ATTX system but wouldn't advise that as they are crap,or you can buy the Fox TXR system which is brilliant.I sometimes use bank sticks rather than a pod,so having a receiver is convenient.As I have said,the Fox STR's are serving their purpose so I will stick with them for now.
Defiant MPS are in the process of marketing their new alarms and from what I've read and heard about them they are the dogs wotsits.I have to say that anything where Keith Fielding is involve in will be absolutely spot on.I know the alarms aren't going to be cheap but they probably will be the best alarms out.
Mind you,at the end of the day it's all down to personal preference,for me if the alarm makes a noise when line is pulled,then thats good enough for me.