Gemini or GPT-4o for email marketing: which one writes better for your SMB?

Gemini or GPT-4o for email marketing: which one writes better for your SMB?

If you want to automate your email marketing with AI, you will quickly run into two names: Gemini from Google and GPT-4o from OpenAI. Both models promise to save you time on writing commercial emails, newsletters, and follow-ups. But which one actually delivers better results for a small or mid-sized business? In this article, we compare Gemini vs GPT-4o specifically for AI email marketing in SMBs. You will learn what sets the models apart, how to get the best results from each, and when to use which.

Why AI email marketing deserves serious attention for SMBs

Email marketing is still the highest-ROI channel for many service providers and e-commerce businesses. At the same time, writing good emails takes time. A strong subject line, a personal opening, a clear call to action, and the right tone for your audience: if you do it properly, you are looking at at least half an hour per email.

With GPT-4o for email writing or Gemini for business use, you can bring that down to five to ten minutes per email, including revisions. That sounds straightforward, but the difference between the two models is bigger than you might expect, especially when writing for a Dutch-speaking audience with a specific brand voice.

How GPT-4o performs on commercial emails

GPT-4o is currently OpenAI's strongest general-purpose language model for text generation. The model has been trained on a huge volume of commercial and marketing content, and that shows in the output. GPT-4o writes naturally, persuasively, and with a clear sense of structure.

What GPT-4o does well in email marketing

Say you need to write a follow-up email for a quote you sent three days ago. An effective prompt for GPT-4o looks like this:

"Write a professional follow-up email in Dutch for an IT service provider. The recipient received a quote for managed IT support three days ago. Tone: friendly but direct. Maximum 150 words. Include a concrete call to action to schedule a phone call."

With a prompt like this, GPT-4o consistently produces emails that are ready to use. The model understands the commercial context, defaults to an active writing style, and avoids vague phrasing. The subject line it generates is usually sharp and click-worthy.

Where GPT-4o really stands out is its ability to adjust tone and style based on your instructions. Tell it your audience consists of directors at SMBs in the construction industry, and the model automatically adapts its word choice and examples accordingly. That flexibility makes it particularly useful for businesses that serve multiple target groups.

Limitations of GPT-4o for email marketing

GPT-4o tends to produce generic emails when given shorter instructions. If you do not specify your prompt carefully, you get text that is correct but lacks personality. For newsletters with multiple sections, the model can also lose the thread when the instruction is too broad.

How Gemini performs on commercial emails

Gemini, Google's language model, has made significant quality improvements over the past few months. Gemini for business use is especially interesting for companies already working within the Google ecosystem, think Gmail, Google Workspace, and Google Ads.

What Gemini does well in email marketing

Gemini has a clear advantage when it comes to context and current information. The model can be connected to Google services and has access to recent data, which is useful for newsletters where you want to reference the latest developments in your industry.

A concrete prompt for Gemini when writing a newsletter:

"Write a monthly newsletter for an accounting firm with 15 employees. Topic: three tax changes that SMB owners need to know about in 2025. Tone: professional but accessible. Length: 300 words. Close with an invitation for a free consultation."

With prompts like this, Gemini produces well-structured content with a clear layout. The model is naturally somewhat more formal than GPT-4o, which is actually an advantage in certain industries such as accounting, legal services, or financial advice.

Limitations of Gemini for email marketing

Where Gemini falls short is commercial sharpness. Subject lines are sometimes too neutral, and the call to action tends to feel informative rather than motivating. For e-commerce businesses writing emails to drive direct conversions, GPT-4o generally performs better.

Gemini's Dutch language quality is good, but not always natural. The model occasionally chooses phrasing that is grammatically correct but sounds slightly too stiff for personal client communication.

Gemini vs GPT-4o: a direct comparison for email marketing

Here are the key differences at a glance:

• Commercial sharpness: GPT-4o wins. It writes more persuasively with stronger calls to action.
• Formal tone: Gemini wins. Better suited for industries where professionalism matters more than conversion.
• Integration with Google Workspace: Gemini wins. If you use Gmail and Google Docs, the workflow is simpler.
• Adapting to brand voice: GPT-4o wins. The model responds more precisely to style instructions.
• Processing current information: Gemini wins. It has access to more recent data.
• Dutch language fluency: GPT-4o wins, though the gap has narrowed.

When should you use which model for AI text generation in your SMB?

The choice between Gemini and GPT-4o depends on your specific situation. For e-commerce businesses writing campaign emails, abandoned cart emails, and promotional newsletters, GPT-4o is the better choice. The model understands commercial urgency and translates that into text that gets people to act.

For service providers such as accountants, lawyers, coaches, or consultants who regularly send informative newsletters to their client base, Gemini is a serious option, especially if you are already deep in the Google ecosystem.

The most practical approach for an SMB with five to fifty employees is to start with GPT-4o via ChatGPT or the API, build a fixed prompt structure for your most common email types, and test it with your own audience. After four weeks, look at your open rates and click-through rates. That data will tell you more than any benchmark.

How do you maintain consistent quality with AI email marketing?

The biggest mistake SMB owners make with AI text generation is using prompts that are too vague. A good prompt always includes: the target audience, the desired tone, the goal of the email, the maximum length, and an instruction about the call to action. With those five elements in your prompt, the quality of the output improves noticeably, regardless of which model you use.

If you want to go a step further, you can automate email workflows using tools like n8n or Make, where GPT-4o or Gemini automatically generates personalized emails based on customer data from your CRM. That is the point where AI email marketing for SMBs becomes truly scalable.

Take the next step with AI automation for your email marketing

Choosing between Gemini and GPT-4o is ultimately a practical decision, one best made based on your industry, your tool stack, and your goals. What is clear is that both models can drastically reduce the time you spend on email marketing, as long as you instruct them well and integrate them properly into your workflow.

Want to know what an AI automation strategy looks like for your specific business? Schedule a free discovery call at 5cagency.nl and find out which approach delivers the most for your situation.