As a housing lawyer, in the private rented sector, generally the stereotypes are like this. Landlords are all Rachmanite earslings, according to tenants. Tenants are all ungrateful scumlets, according to landlords. Letting agents, though, are reviled by both sides.
A letting agent is a person who, for a fee, will advertise a property that a landlord is putting up for rent. They will also, in some circumstances, collect rent, serve notices, and serve as the point of contact for any disrepair or similar. The idea is that a landlord who, for whatever reason, has other things to do aside from managing his properties can leave it up to the agent for a nominal fee and then get on with other things.
Unfortunately, and herein lies the reason why letting agents are so reviled, there is no guarantee that the agent will be competent at all, as anyone with a shiny suit and a fancy shingle can set themselves up as one. No certification, professional membership, or other qualification is necessary. Which means that if the agent cocks it up and gets you into deep doo doo, your only recourse is to fire and/or sue them. And they don't have to have insurance for that so it may be throwing good money after bad.
I think I should elaborate on this from both perspectives.
Tenants hate letting agents because the stereotypical letting agent is a dyed in the wool Friend of Hoogstraten. Tales abound of agents doorstepping tenants, being aggressive and threatening when demanding rent but when it comes to the agent being informed of their repairing obligations, dragging their heels and dodging it, probably because they don't want to be shot as the messenger when going to the landlord cap in hand for money for repairs. Then there are letting agents who serve notices to quit unilaterally on a whim, who even carry out unlawful evictions for fun and profit, and who have little more than a passing acquaintance with the provisions of tenancy deposit protection. And they tend to try and pass on hidden charges to the tenants as well.
While landlords hate letting agents because, well, if you want something done properly, you ought to do it yourself. They might be good at getting you prospective tenants but how do you know that they're picking the right ones - i.e. that will pay the rent on time, that won't trash the place or similar. Also, charging extortionate commission is often a charge levied at them, and another common dispute is where the letting agent holds onto the rent and does not pass it onto the landlord. In fact, this occurrence annoys both sides because what happens is that the tenant gets hit with possession proceedings when the landlord notes that no rent is forthcoming, defends on the grounds that he did pay all the rent to the agent but the agent fails to pass it on, then gets hit with a costs order at the hearing because of the tenant's successful defence - which the landlord ends up having to pay owing to the agent's dishonesty. Agents also have a stereotype of being lax with notice procedures and giving incorrect notice to tenants in default, which wastes yet more time and money.
The number of tenancy disputes which have come about because of a crap letting agent are innumerable. Just to illustrate the damage that a crap agent can do, here's a case study. Mr & Mrs Smith are tenants of Mr Brown. They were let this property through an agent, Bullion Lettings. Bullion Lettings collect the rent on time every time but then... sit on it, because they're dissatisfied with the commission that Mr Brown is paying them and are feeling vindictive (and also Mr Ramsbottom their head honcho wants a new Jag). They hold out the rent but claim that the tenants aren't paying it. Mr Brown claims in Court for possession. Mr & Mrs Smith point to the receipts they've kept of the rent. Mr Brown tries to fire the letting agent. The letting agent says, "but you owe me £lots of money in commission!" The tenants also counterclaim for non-protection of deposit (more on that in another node and for disrepair. The landlord says, "what the cunting fuck is going on here?!" and then makes a third-party claim against the agent because he had contracted with the agent to manage the property. The agent then counterclaims for commission owed against the landlord and continue to blame the tenant. Everyone gets mired in huge legal costs, the tenants end up facing the stress and/or expense (if not eligible for legal aid) of facing eviction, the landlord ends up with his bank account plundered, and the agent absconds and sets up under a completely different name. The landlord then decides to manage the property directly, as his trust in the lettings agency business is forever broken, and ends up spending his time managing the property which defeats the point of instructing a letting agent in the first place.
The impression I get of letting agents in my dealings in cases where they are involved is that they're very good at getting tenants into properties but bloody awful at managing them, on the whole. That, and they tend to talk an endless stream of bollox, exaggerate the truth, and generally cock about, which results in unrealistic expectations on all sides.
That, and the stereotypical letting agent looks like a contestant on The Apprentice and is just as full of shit.
(Node 8 of 30 of my IRON NODES).