Easy to clean (no fiddly crevasses)...small footprint (ie doesn't have a huge base that you will always be tripping over)...good safety features (good extendable harness, stable enough not to tip over if toddler is climbing in, not fiddly bits where fingers can get caught)...size and shape of tray (I looked for one with maximum flat area on the tray - helps when they're a bit older and happy to sit up there doing pictures/playdough, etc). I also wanted one that I could store easily - mine folds flat - it's handy to keep in the shed for when guests with little kiddies come to stay.