The latter, in my experience. DD loved to put first potty on her head (it was early, about 15mos, to give her her due) and stand in it but when it came to sitting down it clearly just wasn't comfortable for her. I think it was because she was little and has a tiny bum! Luckily it was £2 at an NCT sale. By chance, at the next sale, came across a more chair-like one, for £3. Bought it on a whim, Madame took to it and used it as a chair for a couple of months, she sat on her own throne while I was on mine, both of us 'reading'. It was quite companionable. And also meant that we caught quite a lot of wees by accident (followed by wild jubilation of course) and I'm sure it contributed to her really getting it quite quickly, before we'd really done any 'training'.
Moral of the story - buy cheap/secondhand ones in a couple of different designs and experiment. Oh, and a loo seat too, in case your DD prefers to go 'like a big girl lady' (to quote my DD). I found it was invaluable to have them scattered around the house anyway (even now, 4 months on) in case of short notice being given, so it wouldn't be a waste of wonga.
Oh, and DD now likes the original one too, as she decorated it with stickers and likes to point them all out, one by one, when she uses it.