My second toy was a butt plug, Ryder, and it was decidedly different than a dildo. This was over two years ago, now.
That popping sensation as it moved into place, and the fullness it provided... It is difficult to forget something like that. As I was relatively new to anal at the time, it felt so foreign and nice.
I still like them to this day, and they have become my favourite type of toy, bar none.
My favourite so far is the Pure Plug Large, though the Pure Plug 2.0 is on the way. It's exciting!