Helm on a VPS is a mixed bag. I had one terrible time installing the free 30 day trial...but it is done. Some people have few problems..some have tons of them. After the thirty day free trial..it's $30.00/month..so consider that...they don't care if it's a VPS or a dedicated server.
This was on a tiny VPS from ezzi.net that has less than 1GB available after the OS files are factored in..so...it's not a huge thing like Plesk.