Pros:
The level of support and responsiveness is something I've never experienced using any platform. In the live chat the co-founder himself is personally helping me get set up on an almost daily basis.

Unlimited sending accounts and warm-up is a dream come true for any high-volume senders like us.

We use multiple sending accounts within a single campaign, and the auto-rotation feature saves us a ton of time from having to manually segment lists into smaller chunks.

Having tried most warm-up products that charge per inbox, I can confirm that Instantly's warm-up is just as good if not better. I was told that it's built by an Ex-Googler from the Gmail team who understands the algorithms behind email deliverability on a deep level.

We're going to be saving $2065 every month since the software that we used to pay a premium for on every sending account will no longer be necessary.

When the roadmap gets fully completed, I honestly just don't see how other solutions would be able to compete.

Cons:
I might be biased but there's nothing significant enough to be worth mentioning.