The old model had individual chairs that anchored in various positions into a flat floor. That's the purist MPV arrangement and is ultimately more versatile because you can, for instance, turn them around for a meeting (picnic more likely).
But hang on, what if you get to Ikea to buy the flat-pack and realise you need to take a seat out? Or what happens if you live in an upstairs flat and have nowhere to store unused - and unfeasibly heavy - seats? Too much trouble.
So instead, the new Galaxy has fold-into-the-floor seats. You get three in the middle row and two behind. All recline and slide, so you can adjust the legroom to whatever inside leg measurements you have aboard.
Also, because the floor is stepped rather than flat, and because the seats have more compact anchors than the old removable ones, there's plenty of footroom beneath them. You can get six-footers in for a longish journey and that certainly wasn't possible before. And they'll have room for some bags behind them.
Back with the S-Max versus Galaxy debate, the two share the same underpinnings, dash (more or less) and driving position. Apart from exterior style and suspension tune, and the fact you can't get the S-Max's five-cylinder 220bhp turbo engine in the Galaxy, the main difference is the rearmost seats. The Galaxy's sleeker little bro' has lower-mounted, non-sliding, non-reclining seats, which effectively cut legroom for the poor saps relegated to the back.
So the Galaxy is a seven-seater, the S-Max a 5+2. The S-Max is also two grand cheaper, as well as more stylish and more fun. Bear it in mind if you don't need the full seven.