A good pal of mine got a tenant through an agency last year. The guy ticked every box imaginable; I’d have gone for him myself. And then he just went rogue. It can be just bad luck.
The law is an ass unfortunately; bad tenants and bad landlords should both be hammered.
@Sanderson many letting agents are small. It makes sense to get one that is close by, all else equal. Some of them do sales as well but it is a pretty different business than selling big houses in Monkstown like Sherry Fitz does.
If you have an apartment try to find a letting agent that already does management for other units in the same development as they will know the ins and outs.
Agents are not a panacea though. If a tenant stops paying rent there is not much the letting agent can do.
Fees in my experience are in the 5%-8% range plus VAT @23%. Deductible against tax of course.