I have used trimlux and it has worked very well for me in the past, not sure what Nick means when he says you can't trim it against a shower cubicle, it is easily cut and butted up to screen/frame.
@on/off , of course you have to fill it with Silcione, thats how it is meant to work, we recently saw a job where someone installed cladseal (made by same people as Trimlux) where they never filled it with silicone, no kidding thats how stupid some installers are, panles had to be taken off wall and seal fitted properly, absolute clowns out there.
my experiece is if you install it as meant to, it will work perfectly, if you install it incorrectly its going to fail, like anything i guess.