In 2025, the AI assistant market has exploded. ChatGPT, Gemini, Claude, Copilot, Perplexity, Hey Friday, and a dozen others all want to be your go-to AI. Each has real strengths and real weaknesses. Choosing the wrong one means either overpaying for features you do not use, or missing capabilities you actually need. Here is how to think through the decision.
Start With Your Primary Use Case
The single most important question is: what will you use an AI assistant for most of the time? The answer dramatically narrows your options.
If you want a voice assistant — one you can talk to and that talks back — most AI assistants are surprisingly bad at this. They were built for text. Hey Friday is built specifically for voice interaction: it uses your phone's on-device speech recognition, responds naturally, and supports a wake word on Android.
If you need deep research — summarizing papers, analyzing documents, web search — Perplexity and Claude tend to excel. ChatGPT with browsing is also capable here.
If you need coding help — GitHub Copilot and Claude are generally the strongest. ChatGPT is competent but shows its age in fast-moving areas.
If you want an all-rounder — something for daily questions, writing, and general assistance — ChatGPT, Gemini, and Hey Friday all work well. The differentiators are price, privacy, and how well they work on mobile.
Privacy: The Question Most Guides Skip
Most AI assistant comparison guides focus on benchmark scores and feature lists. They skip the question that matters most for daily use: what happens to your data?
Every AI assistant that processes your queries in the cloud collects some data. The important questions are: Is your data used to train future models? How long is it retained? Can you delete it? Is your voice (not just text) sent to the cloud?
Read the privacy policy before committing to any AI assistant you plan to use for personal conversations, health questions, or sensitive work matters. If the privacy policy is vague about training data, assume your conversations are being used.
Price: What You Actually Get for Free
Every major AI assistant has a free tier, but the limits vary enormously. ChatGPT's free tier uses GPT-4o Mini with limited access to the full model. Gemini's free tier is genuinely capable. Hey Friday's free tier gives 100 chat credits per day — enough for substantial daily use — plus unlimited basic image generation.
The question is not just how much you get, but what happens when you hit the limit. Some AI assistants stop responding entirely. Others slow down. Others switch you to a weaker model without telling you. Know the policy before you rely on a free tier for important work.
Mobile Experience: The Overlooked Factor
Most AI is used on mobile, but most AI assistants are designed for desktop. The result is apps with tiny text, awkward interfaces, and voice input that feels like an afterthought. Before committing to an AI assistant, spend a week using it exclusively on your phone. The friction differences between well-designed and poorly-designed mobile AI are enormous.
Progressive Web Apps (PWAs) deserve special consideration. They install from the browser, work like native apps, update automatically, and do not require App Store approval. Hey Friday is a PWA: add it to your home screen from Safari or Chrome and it works exactly like a native app, including fullscreen mode and offline caching.
Model Quality vs. Interface Quality
A common mistake is choosing an AI assistant based on the underlying model rather than the complete experience. The model matters, but so does latency, how well the interface handles long conversations, whether the AI remembers context, and how natural the voice interaction feels.
A slightly less capable model delivered with lower latency and a better interface often produces better real-world results than a more powerful model wrapped in a frustrating UI.
The Checklist
Before choosing an AI assistant, run through these questions:
- Does it support voice input and output, or is it text-only?
- What happens to my conversations — are they used for training?
- What does the free tier actually include, and what are the hard limits?
- How does it perform on mobile specifically?
- Is it available as a PWA or does it require a native app download?
- Does it support the AI models I want to use?
- What is the latency like for voice responses?
There is no universally correct answer. The right AI assistant is the one that fits how you actually work, not the one that scores highest on synthetic benchmarks.
Context Window: More Important Than Benchmark Scores
Benchmark tables get the attention, but for everyday use the context window matters more. The context window is how much text the assistant can hold in mind at once — your question, everything said earlier in the conversation, and any document you have pasted in.
When you exceed it, the assistant does not warn you. It quietly forgets the earliest part of the conversation. This is the single most common cause of the complaint "it was doing fine and then it started ignoring what I told it." Nothing broke; the instruction simply fell out of the window.
What this means practically: if you routinely paste long documents or hold hour-long conversations, a model with a larger context window will feel dramatically more capable than one that merely scores better on reasoning tests. If you ask short, self-contained questions, context size is close to irrelevant and you should optimise for speed instead.
The Lock-In Question Almost Nobody Asks
Before committing to an assistant, ask what happens if you leave. Three specifics are worth checking:
- Can you export your conversation history? Some services offer a one-click export. Others offer nothing, and years of useful exchanges become unrecoverable the day you cancel.
- Do your saved prompts or custom instructions travel? Almost never. Assume you will rebuild them.
- What happens to your data after you delete the account? Look for a stated retention period rather than a vague assurance. "Deleted immediately" and "deleted within 90 days from backups" are very different commitments.
None of these are reasons to avoid a service. They are reasons to know the exit cost before the cost is sunk.
How to Test One Properly in Twenty Minutes
Marketing pages and benchmark charts will not tell you whether an assistant suits your work. A short structured trial will. Use the same four prompts on every candidate:
- Something you already know the answer to. This is the only reliable way to detect confident errors. If it gets a question wrong in your own field, treat every answer outside your field with the same suspicion.
- Something genuinely current. Ask about something from the last week. You are testing whether it searches, whether it admits it cannot, or whether it invents an answer. The third behaviour is disqualifying.
- A long, messy, real task. Paste in an actual email thread or document and ask for a summary and next steps. Polished demo prompts hide the weaknesses that real input exposes.
- A follow-up that depends on the answer above. This tests whether it actually held the conversation in mind, or is answering each message in isolation.
Twenty minutes across three assistants will tell you more than a week of reading comparisons — including this one.
Red Flags
A few signals reliably predict frustration later:
- No stated data policy, or one that requires a lawyer to parse. Clear services say plainly whether your conversations train their models.
- Training on your data with no opt-out. Some services let you turn this off; some tie the opt-out to a paid plan; some do not offer it at all.
- Confident answers with no citations on factual questions. An assistant that cannot show where a claim came from cannot be checked.
- A free tier that quietly degrades. Watch for silent downgrades to a weaker model once you hit a limit, rather than an honest "you have reached your quota".