Ok I have personal experience with this, having volunteered at an animal sanctuary. The neighbour of the sanctuary was reported to the RSPCA for keeping animal in poor conditions, these were farm animals and horses.
The RSPCA came out, closed him down, small scale farmer, and shot many of the animals, not even attempting to rescue them, they left the flock if sheep and in their absence we proceeded to move the flock to one of the sanctuaries fields. When the RSPCA returned they were not happy and the owner of the sanctuary refused to hand over the sheep, saving them as they were there to shoot the entire flock!!!! Many animals died there, needing a little tlc not death, being that a sanctuary was just next door too it wouldn't have hurt them to ask if we would take any animals.
So, yes they do good, but the also spend millions on posh new headquarters in a tiny village in Sussex, where I grew up, and is ridiculously expensive to live!! So land is at a premium! Fat cats lining their pockets, leaving less for the animals in need xx