This is fully anecdotal so keep that in mind. I've looked and haven't found any studies comparing them in any depth.
HHC seems a little more anxious and stimulating than standard THC to me. Increased heart rate compared to THC, increased incidents of racing thoughts, paranoia, etc. It seems to lower blood pressure to a similar or identical degree to THC. Terpenes might play a role in the difference. The HHC I've tried was always alone whereas I usually consume THC via bud or oils that have added terpenes. Terpenes can definitely cause a high to lean more stimulant or sedative depending on the combination. So it may well not be a property of HHC itself leading to my experience. I'd have to try HHC with added terpenes to be sure.
All of this was only moderately increased over standard THC but I've messed with HHC a lot over the years and it was consistent. I've read a lot of people claim that HHC feels very "sativa" which I suspect might be touching on the same thing as above.
Other than that, due to it being minimally studied, it's possible there are adverse effects from long term use that THC lacks, so I'm uncomfortable saying the risk profile is identical, though I'm confident that it's similar.