Hi Rents,
In my experience anything that is "too good to be true" usually is... Just to clarify though - is this a letting agent saying that they'll guarantee the rent on a property you own as well as taking care of tenant finding and all the legals etc?
either way 15% seems a bit high to me - it tends to eat away at your profits and let's be honest, we ain't a charity
Are they really doing something that you can't do yourself? It's all down to how you leverage your time in the end and how much you're prepared to pay for the service...
If it's just a rent payment guarantee you are after there are schemes that will cover that for you that I use all the time.
I'm a great believer in self managing whenever you can.
Keep us posted on this.
Cheers, Tim