Was, when it came out, since then MJ have released 3 new models (plus variants) and most users assess the MJv5 model as more powerful. Of course new SD models are also on the horizon…
SDXL is available at https://beta.dreamstudio.ai/ though they say they're going to release more variants.
I think ControlNet is a lot more interesting than just "better tuned models"; it means there's no line between creating something yourself and asking an AI to do it anymore.