I HATE it - I understand it, but I HATE it. There are other ways. I won't do the bandwagon debate here, but I live it off-site!
All of our horses, except one) have been rescues. Our one breeder purchase was my sister's dressage mare - a warmblood cross out of a rescued (off-track) Standardbred mare by a Hanoverian stallion. Lowdee was sweet and smart, but she was a ditz. Despite being a beautiful cherry bay, she was certifiably, genetically blonde!
Our rescues - all seven of them, including a pair of very silly ponies - have been absolute gems. Sound, sane and solid. I will NEVER buy a horse from a breeder. We'll be looking for a new riding horse for DD in a couple of years - Joey's getting up there, but she's got to get through college before starting her next horse project - and we'll be looking at the rehab places around us. Every one we take in frees up space for another one - or two - to get out of the pipeline.
For what it's worth - our dogs (two, at the moment) and cats (four) are all rescues, too. Two came right off the street, one was an active mistake (... oops ... adoption ... sorry, Crazy Dog) the rest are failed fosters. I wouldn't trade any of them, even Crazy Dog, who I am gradually learning to call by her given name (Skye?) now that she's finally learned how to behave.
Even my chickens are rescues ... the main flock is of critically endangered Nankins, so we're helping to save a breed. The others are Kindergarten dropouts and their offspring - brought home from school to keep them from going to freezer camp (YOU try to turn down 17 five and six year olds asking you to "PLEEEEASE take our babies home!" I dare ya!)