Tell me what I need in a tripp trapp

[sste]

Was there a change in design recently or is buying any one of the internet an OK strategy? Do they all come with those sled-bottom looking things to prevent pushing off a table and tipping?

Also, would you buy a cushion - - they are kind of pricey? I am def. buying the tray aftermarket thing but since my son is 20 months I was thinking of skipping the babyset.

Please advise!