I just realized that Illustrious turned a year old on the 25th. but it became open to download by anyone on the 30th so I guess it still counts today? I think it has totally displaced Pony in almost every field, and shows no signs of being replaced itself (newer models are much more resource intense and/or locked down). The 1.0 and further releases wound up being total flops nobody bothers with.
Random pic from my saved images that I made with an Illustrious based model.