My verdict: unbeatable value for money for volume cold email.
The unbeatable value for money on the market. It's my 'go-to' tool for aggressive scaling (sometimes a bit 'dirty', but effective).
The API is good, scalability is ultra-simplified with unlimited warm-up. If you want to send massive volume without breaking the bank and without friction, it's the reference.
What I like less: the UX is raw, it's volume not high-touch, and no native multichannel.
My advice: if you want to scale hard on cold email, it's Instantly. For quality individual outreach, look at Emelia or Lemlist.