Stress-tested Opus 4.5 vs Gemini 3 Pro with Greg Isenberg

Happy Wednesday squad,

Quick note: decided to extend the $199/year for life deal through Black Friday.

Claim the $199/year pricing for life here : https://www.skool.com/the-vibe-marketers

Alright, I did something cool yesterday!

New episode with Greg on the Startup Ideas Podcast where we stress-tested Claude Opus 4.5 vs Gemini 3 Pro live!!

Same startup idea. Same prompt. Went from concept → landing page → clickable prototype to see who wins.

But it turned into something else where I ended up showing my whole Claude Code setup for design, copy, ads. The stuff that makes vibe-coded sites actually convert.

Here's the TL;DR of this episode:

#1 We grabbed a startup idea from IdeaBrowser - EstateClear, a family dashboard for keeping everyone informed during probate. Less phone tag with anxious relatives, fewer billable hours going back and forth with attorneys.

#2 Gave the exact same prompt to Opus 4.5 and Gemini 3 Pro. Build a landing page. Turn it into a clickable prototype. No cherry-picked screenshots, just let's see what ships.

a. Opus 4.5 felt like having a senior engineer next to me.

- stayed on track, less bug hunting, doesn't get lost in the codebase
- design was clean and refined
- avoided the typical AI gradients and purples, didn't look vibe-coded
- prototype felt like a real product

b. Gemini 3 did something I didn't expect.

- started adding AI features we never asked for: creative, but unexpected
- more human: social vibe, emojis, different illustration style
- we tried Anti-Gravity: used Nano Banana Pro to generate a mockup first before writing any code.

#3 Most vibe-coded stuff falls apart on conversion. So I broke down how I fix that with two Claude Code skills:

a. the front-end design skill most people don't know exists
b. my "elevated direct response" copy setup - researched how Hormozi and Cody write, fed Claude my tweets, video transcripts and newsletters. Now, it nails my voice every time

#4 Showed how I have been using Gemini 3 Pro to research top-performing ad formats across industries + Nano Banana Pro to create the visuals for ads.

This isn't vibe coding anymore. It's vibe building.

A year ago you would have needed an entire village to pull this off.

Now, you don’t even need to know how to code to go from idea → landing page → prototype → ads → revenue. The whole path is open.

And, if you want to be around people actually building with AI, The Vibe Marketer’s community is where you can start along with 2700+ vibe marketers.

You get workshop replays, resources, my bi-weekly hot seats, and live sessions with expert marketers building with AI.

This month we've got two mentor sessions: idea to app without coding (Dec 11) and building authority with AI (Dec 16).

$199/year for Black Friday. Goes back to $299 after.

See you on the inside?

- James