I feel I am a bit late to the AI party. If I'm honest, I was reluctant to take the plunge, because I love coding so much.

But lately I have taken more and more to ask ChatGPT 5.1-Thinking for code, and I have to reluctantly admit that it spits out useful code. And yes, much much faster than me.

So I feel I now need to use a proper AI assistant to assist in coding.

At that point, I am mainly interested in using AI for small to medium flutter apps.

Can anyone with a bit of experience with these tools give me some recommendation as to what the best tools are?

As far as I can see there are 2 dimensions (Integration and AI Model), with the top contenders being:

1) Integration

    1a) VSCode fork (Cursor)

    1b) VSCode extension (Github copilot)

2) AI Model

    2a) ChatGPT 5.1

    2b) Claude Sonnet 4.5

My criteria are code success (meaning I want the setup to spit out code that actually solves the task) and privacy (probably a tall order, but I'd like a setup that does not openly send companies the inner details of my code, my secret keys, etc).

I also wonder about costs, in particular if I'll have to duplicate subscriptions (e.g. have a chatgpt subscription + a cursor one, or if I can use an existing chatgpt subscription with an integration solution without paying an additional subscription).

I would be grateful for any recommendation/feedback/random thoughts.