I've had two meta alarms and a number of datatool alarms over the last 10 or so years.
My preference is for the datatool ones. They work for longer before failing in my experience.
Both meta alarms developed faults with the movement sensors after 3 to 4 years, and started going off all the time. Alarms were removed as the cost to replace was the same as original fitting.
Two of the datatool alarms developed faults and needed new pcbs to be fitted, but this was after about 5 years. I was able to buy these from a wholesaler and fit them myself (from memory it cost £35 for the pcb alone, or £85 with a new pair of remotes - to upgrade to the latest veto evo style from an older version).
I've also had some datatool alarms that have worked flawlessly for longer than this, just incase your expecting them to all fail eventually
I don't have alarms on my current bikes, both of which have factory imobilisers. If someone wants them bad enough they will take them regardless of what you do, ground anchors, chains, etc can all be defeated with the right equipment.
A mate who is now on here too had his blade stolen outside a hotel. It was disc-locked front & rear, alarmed, and chained to iron railings. Went in the middle of the night and no one saw a thing...