OpenAI has officially released GPT-5.2, and the reactions from early testers — among whom OpenAI seeded the model several days prior to public release, in some cases weeks ago — paints a two toned picture: it is a monumental leap forward for deep, autonomous reasoning and coding, yet potentially an underwhelming "incremental" update for casual conversationalists.Following early access periods and today's broader rollout, executives, developers, and analysts have taken to X (formerly Twitter) and company blogs to share their first testing results. Here is a roundup of the first reactions to OpenAI’s latest flagship model."AI as a serious analyst"The strongest praise for GPT-5.2 centers on its ability to handle "hard problems" that require extended thinking time.Matt Shumer, CEO of HyperWriteAI, did not mince words in his review, calling GPT-5.2 Pro "the best model in the world." Shumer highlighted the model's tenacity, noting that "it thinks for **over an hour** on hard problems. And it nails tasks no other model can touch."This sentiment was echoed by Allie K. Miller, an AI entrepreneur and former AWS executive. Miller described the model as a step toward "AI as a serious analyst" rather than a "friendly companion.""The thinking and problem-solving feel noticeably stronger," Miller wrote on X. "It gives much deeper explanations than I’m used to seeing. At one point it literally wrote code to improve its own OCR in the middle of a task."Enterprise gains: Box reports distinct performance jumpsFor the enterprise sector, the update appears to be even more significant. Aaron Levie, CEO of Box, revealed on X that his company has been testing GPT-5.2 in early access. Levie reported that the model performs "7 points better than GPT-5.1" on their expanded reasoning tests, which approximate real-world knowledge work in financial services and life sciences."The model performed the majority of the tasks far faster than GPT-5.1 and GPT-5 as well," Levie noted, confirming that Box AI will be rolling out GPT-5.2 integration shortly.Rutuja Rajwade, a Senior Product Marketing Manager at Box, expanded on this in a company blog post, citing specific latency improvements. "Complex extraction" tasks dropped from 46 seconds on GPT-5 to just 12 seconds with GPT-5.2. Rajwade also noted a jump in reasoning capabilities for the Media and Entertainment vertical, rising from 76% accuracy in GPT-5.1 to 81% in the new model.A "serious leap" for coding and simulationDevelopers are finding GPT-5.2 particularly potent for "one-shot" generation of complex code structures.Pietro Schirano, CEO of magicpathai, shared a video of the model building a full 3D graphics engine in a single file with interactive controls. "It’s a serious leap forward in complex reasoning, math, coding, and simulations," Schirano posted. "The pace of progress is unreal."Similarly, Ethan Mollick, a professor at the Wharton School of Business at the University of Pennsylvania and longtime LLM and AI power user and writer, demonstrated the model's ability to create a visually complex shader—an infinite neo-gothic city in a stormy ocean—via a single prompt.The Agentic Era: Long-running autonomyPerhaps the most functional shift is the model's ability to stay on task for hours without losing the thread.Dan Shipper, CEO of thoughtful AI testing newsletter Every, reported that the model successfully performed a profit and loss (P&L) analysis that required it to work autonomously for two hours. "It did a P&L analysis where it worked for 2 hours and gave me great results," Shipper wrote.However, Shipper also noted that for day-to-day tasks, the update feels "mostly incremental." In an article for Every, Katie Parrott wrote that while GPT-5.2 excels at instruction following, it is "less resourceful" than competitors like Claude Opus 4.5 in certain contexts, such as deducing a user's location from email data.The downsides: Speed and RigidityDespite the reasoning capabilities, the "feel" of the model has drawn critique.Shumer highlighted a significant "speed penalty" when using the model's Thinking mode. "In my experience the Thinking mode is very slow for most questions," Shumer wrote in his deep-dive review. "I almost never use Instant."Allie Miller also pointed out issues with the model's default behavior. "The downside is tone and format," she noted. "The default voice felt a bit more rigid, and the length/markdown behavior is extreme: a simple question turned into 58 bullets and numbered points."The VerdictThe early reaction suggests that GPT-5.2 is a tool optimized for power users, developers, and enterprise agents rather than casual chat. As Shumer summarized in his review: "For deep research, complex reasoning, and tasks that benefit from careful thought, GPT-5.2 Pro is the best option available right now."However, for users seeking creative writing or quick, fluid answers, models like Claude Opus 4.5 remain strong competitors. "My favorite model remains Claude Opus 4.5," Miller admitted, "but my complex ChatGPT work will get a nice incremental boost."