Are rental guarantees securing your rent and investment?

A website advertises: (quote) "Buy to Let Investment Plan : You purchase a luxurious one bedroom apartment for £54,000 (£47,000 + VAT)*. You put £16,000 and the remaining £38,000 is mortgaged for 20 years. Your monthly installment will be around £300. The rental income (guaranteed by our accommodation division) is around £350. This means an annual rental return of 8%! In addition to this, you will also have the annual appreciation which is estimated to be more than 10%."
When reading such offers, you should run fast !

First, read the scams that are being committed with rental guarantees:
Consumer alert of rental guarantee scams
Facts about guaranteed rental schemes

You should ask yourself the following questions:
Who issues the guarantee - is it a bank guarantee or a guarantee by company or developper which might go out of business tomorrow?
Is the apartment currently tenanted and if so, what is the base net rent that you would get without that "guarantee"?
If you are buying a nice apartment in a good locatin, why do you want to join a pool where your "nice" apartment guarantees the rent for the "not so nice ones"?

This is what you do in Germany:
You instruct a rental or condominium administration to take care of your flat. They are keen to do that for most apartments. The cost for this service is between 15-20€ or 6% of your net rent. They pay all expenses out of this, sign contracts with new tenants, deal with all tenancy and correspondance, make sure the tenants refurbish the apartment when they move out, take care of repairs (providing they are not the tenant´s responsibility) ... and send you your monthly payments. They also engage legal proceedings on your behalf should the tenant misbehave or not pay his dues (this does not happen very often since the government pays the rent for the needy!).
Normally, the rental or tenancy manager will only earn their fee if the apartment is tenanted, which is plenty incentive to ensure that all runs smoothly. If you need a professional tenancy / rent administrator to take care of your properties, please send us a message.

Normally, tenants are requested - by tenancy or rent contract - to carry the cost of minor repairs up to 6% or 8% of their yearly rent - so you are protected against repairs.

If you envisage personal (holiday) use, you should only buy a vacant property and then sign time-limited rental agreements.

If your Berlin property is reasonably decent or if the tenant has already been living in the property for years, rental guarantees are overkill. It´s like buying expensive travelling insurance if you take the train from London to Brighton.