Who is ChatGPT's biggest competitor?

Can you tell me who the primary rival of ChatGPT is in the current landscape of technology and AI-powered conversational systems? Are there any specific companies or platforms that are vying for the same market share and offering similar features, capabilities, or user experiences as ChatGPT? How do these competitors differentiate themselves from ChatGPT, and what sets them apart in terms of functionality, adoption, or user base?