It's fast enough as it is supposed. To me their pricing algorithm also works well.
Only issue is if you are out of stock it does not update the prices of that product and it may cause a big headache. Fortunately, my VA checks my prices frequently and he has realized the problem and now we take a manual action for such cases.
Could anything have been better? It's a little hard to understand and use its interface but I couldn't find a better solution so far, so it's okay.
How was the support? Contacted once, they were responsive, had no other issue.
We actually have a feature which allows you to automatically move your products price to max when a product goes inactive. If you contact support via live chat or email, they can help you implement this.