We’ve got Galt, Hubelino and Quadrilla.
The Quadrilla is nice, looks lovely but it’s a touch awkward for the kids (3&6) to build by themselves, the older one understands that the blocks have different functions but the younger doesn’t. Also it falls over with the slightest touch or misalignment. The kids love that the switch blocks mean your marbles can take different tracks, but for us its fragility means a parent needs to be involved for the whole time they’re playing with it.
Hubelino is satisfying to look at, but can be tricky to build long or high routes unless you have loads and loads of duplo or Lego to build the base with. As long as you build a decent structure then it’s very sturdy and obviously because it’s Lego easy to alter and improve as you go along, though my 3 year old isn’t always very patient about the building process and just wants to get to the marble bit. I’d say Hubelino is good for kids who’d enjoy the building process as much as the marble run bit of it.
The Galt one is my favourite, it’s pretty robust, easy for the kids to play with themselves, doesn’t require getting another box of toys out alongside like the Hubelino/lego does, and there’s extra compatible kits available if we want to expand our collection. I believe it’s also the cheapest of the 3, to end up with a big setup of the Quadrilla or Hubelino would cost quite a bit more.
Out of the ones we have, I’d buy more of the Galt any time and more of the Hubelino when my youngest is a bit older and able to plan and enjoy the building bit. The Quadrilla has just been too fussy for me to be keen on buying an extension set.