The furniture we've had from stores over the last 20 years is 'functional'. Some of it even looks ok, and is reasonably comfortable, but you're never going to win a 'Better Homes & Gardens' competition with it in your gaff. It's great to get you in, and then decide what you actually want to buy (or to wait for sales), but if you're handing any back during your time in the quarter (ie, at an interim time before you move out), make sure the scale (fully-/partly-/un-furnished) is recalculated, and if you're due a reduction in rent, that it's applied. We got ripped off by DIO for 6 years on overcharge of rented furniture (my own fault for not checking) and then they would only redeem the current years charges when challenged.
As far as cleanliness, a major factor is how long since the previous tenants moved out. Much-out standard is generally very high, and rigorously applied, but if a quarter is subsequently vacant for a lengthy period, any cleaning done by DIO (if any at all) is liable to be pretty slap-dash.