Sat 19-Jan-13 12:12 PM | edited Sat 19-Jan-13 01:43 PM by J_Harris
Hi Juro, welcome to Nikonians.
The shorter setup height is what convinced me to buy the four-legged section GT3542LS model. On many occasions it has made shooting from the sitting position more comfortable. I have also discovered the shorter height combined with a "macro focusing rail" is useful for macro work.
As far as the three-legged section model being more stable, Neil and Joe could give much better advice than I can. They have done actual testing with the tripods using the "tap test". I'll bet there would be a minuscule "measured" difference using instruments or formal testing of some kind, but in "real world" usage it wouldn't make any difference. However, I'm not aware of anyone who has tested the newer GT3542LS (2012 model) against the GT3532LS or the GT3541LS that it replaced. Gitzo claims the new "hub" design is stronger, but I have not seen any claims of it reducing vibrations more.
Edited to add: Another thread that has a lot of interesting information about tripod selection is linked below: