I know about a half-dozen people in my area with Riverman offspring. For the most part, they are good looking, typey, athletic horses. Some of them have jumper or dressage type movement, some of them are flatter in their gaits. Most of them seem to be pretty decent at the jump but I know of one gelding who is almost scary with his front legs.
Regarding temperament: one experienced warmblood breeder friend who bred to him three years in a row quit using him because – in her words – “everything is an issue with his foals” (her foals were out of several different mares, too). Another experienced warmblood breeder in our area used him several years in a row on her TB mares, and has not had much success selling the foals, including a 6 y/o gelding who has bucked off a few people (broke one person’s arm pretty badly). Another friend had to take back a yearling filly because the new owner couldn’t deal with the high-spirited temperament. Another friend has a 4 y/o mare by him that she has been trying to sell since she was a weanling. She finally gave up and bred the mare to an Irish Draught stallion to “take the edge” off her temperament. Another breeder I know told me that one of the young horse trainers in her area said he won’t take Riverman youngsters anymore for starting because he has been hurt too many times by them. Another experienced breeder and trainer has a homebred Riverman mare that she just uses for breeding – says she has no desire to ride her and it “isn’t worth the time and trouble” to try to get her sold.
On the other hand, I know two people with Riverman youngsters that they just LOVE. One is 4 y/o gelding doing amateur hunters, and the other one is a 3 y/o mare that the owner hopes to event.
My basic sense is that the Riverman offspring aren’t for everyone. While there are certainly some easy ones out there, most of them seem to be more of a pro type of horse – intelligent, athletic, sensitive, somewhat strong willed, with not much tolerance for being bullied or mishandled, and generally not for the timid or inexperienced. I think his strongest contribution will be his broodmare daughters – I’ve seen some stunning foals out of Riverman mares.