The main difference apart from any perceived social differences between private and sw tenants is who pays the rent. A private tenant will have paid a deposit and will be handing over their own hard earned cash each month and therefore one could assume that they would want that deposit back at the end of the tenancy and therefore are more likely to comply with the covenants in their lease. The SW tenant generally has the deposit paid for them and subsequent rental payments paid to them so there is a higher risk of non payment and damage to property. When you decide to bring the prtb in to reimburse you, the tenant obviously can't pay you back and will no doubt have the great backing of threshold et al to ensure that they can get out of it anyway.
Financially it makes more long term sense (generally) to go with private renters and finances is what its all about.
Financially it makes more long term sense (generally) to go with private renters and finances is what its all about.