If you want another Rationale alternative, Decision Mentor is a good option. It's a more structured decision-making approach based on a criteria-based process, augmented by AI to help you evaluate options and compare them side by side. The app is geared for personal decisions, with features like decision visualization and AI mentor chat-based suggestions to help you along the way.
Another good option is VenturusAI. It's a platform that gives you immediate feedback on business ideas using GPT-3.5 and GPT-4, offering a detailed analysis and suggestions for success. With tools for a broad business analysis, identifying your target audience and creating a customized strategy, VenturusAI is good for startups and established companies that want to flesh out their ideas.
If you're focused on business planning and strategy, Strategizing App is another option. It's an AI-powered tool that lets you build out business models and strategic frameworks, including SWOT analysis and PEST analysis, through an interface that's not too intimidating. It streamlines the strategic modeling process so even people without business modeling expertise can use it.