For me slowness is not the main complaint - after all, my employers pays for that. What annoys me most is its flakiness when dealing with complex setups (multiple cross-account interdependent resources). "A resource failed to be removed" and good luck with the diagnostics.
It can now explode our deployments that create more than 50 ALB rules per MINUTE even faster.
Seriously:
1. Why does it not know about the rate limits other services have.
2. Why does it not automatically retry if it is rate limited.
3. Why is there a rate limit of less than a request per second in the first place!
If you haven’t noticed, I hate CF with the passion of a thousand suns.