I've run them on various vehicles and bikes. Good ones have virtually no stretch, so the pedal feel is firm. However, good oem lines don't stretch either, so the pedal feel is firm.

They can be a worthwhile upgrade if replacing worn or questionable lines. But if your OEM lines are fine, I wouldn't go replacing them.

'97 T-100 SR5
'86 Toyota's, the variety pack (all gone)