I have the Makita.
I've always had problems with it's accuracy, it's very easy to get the fence out of square and so the corresponding biscuit slots. You then end with a, usually very small step in the joint. It's not much, but it's a problem.
I also find that it clogs very quickly, mainly due to the fact that it has a swiveling elbow attached to the inner side of the casting which causes the blockage.
I'd like a Lamello, but have been unsure whether to get the top spec Top 20 or the Classic. I can also see the Domino being useful.
I tend to only use a biscuit jointer on man made materials, finding real wood strong enough butt joined for panels etc.
Just my thoughts.