I actually lost some sleep over this decision on my new cam purchase this year I had a hydraulic roller, solid roller, and solid flat tappet all picked out for the RPM range and intended usage of the engine. I talked to lifter manufactures and cam companies for a few months trying to decide what to do for my new camshaft choice. The hydraulic roller was an attractive choice for a street car but I run my stick car at the track and I love the way an aggressive flat tappet revs. A solid roller was on my list as well but the lifters I should run in a street car were cost prohibitive with the intended use of my car. So I eventually went with a nice medium size solid flat tappet cam that will make the noise I want and the budget stayed low so I could afford some other parts I needed for the car.
When I talked to the owner of Gaterman lifters he told me the reason many hydraulic rollers make noise is because people put too much spring pressure on them. I have a set of springs I cant use because I trusted someones judgement before I contacted the manufacturer that told me they were too firm for a hydraulic roller

Gus