Same here. I love the idea of linear FET driven lights.
Power density is great.
Efficiency is slightly better than with our standard FET+1 or FET+N+1.
I don’t think the hardware is inherently expensive - though I am uncertain here.
Flexibility of adjusting current to match one’s needs is great. F.e. I’d love to PWM SST-20 with 2A at moon and limit to 4.5A at Turbo. Wouldn’t go particularly low but it would have good performance and consistently great light quality.
But such driver is not available.
There’s Texas Commander but it never took off.
There’s Lexel’s driver but it’s in progress.
There’s Led4Power driver but it lacks good UI.
There are several other drivers that have, yeah, medieval UI.
So for now we need to settle at sub-optimal choices. Like PWMing a FET to reduce current. Or adding large banks of 7135s. Or adding resistance. Or using only well-matched cells.
I really hate the state of affairs. But it is what it is and I am unable to do anything about it.