With regards to self-sufficiency, for me, it's a close call between Suicune and Dragonite too.
Dragonite can set up on a lot of pokemon even without support, including a number of rock or even a few ice types. One of the major downside I find with Dragonite compared to Suicune is status really. Being statused with anything sucks for Dragonite, but Suicune with Rest (and Scald for freeze) just doesn't care. If not for that, Dragonite wins for sure, but now it's about even for me.