The downside, as far as i can see, is if you dont clean...you dont get paid.So if we all get wiped out over winter or you are ill for 3/4 weeks, no clean....No payment.
Thats why i have held back a £1000 per month on standing orders, yes i then owe them, (i usually off set it by doing an internal clean, at the next clean) but i will have the money coming in