Great plans, nice design, good customer service
Fake uptime, loading time is crucial, bad form editing tool
After implementing it on the website, it worked well for a time, but unfortunately, with SendInBlue, you cannot be sure that it will work constantly as you tested it.
SendInBlue, uses some kind Ajax, which sends a request with customer's email, and to check and show the message, it takes sometimes over a minute.
Second thing, that it can work today, but tomorrow CDN is offline or the weather is bad, and it stops to work. Customer Service can say that it is working perfectly, however, with several tests, cache, and cookies cleaning, changing devices, the proves are there.
Bad form designing tool. There is a possibility to change the code, however, if you change it, there are 0 chances that you will get the form you just paste to your code :) There is no "no styles" form as in MailChimp, so you have to change codes inside of <style> tag and the worst create your style="" into tags.
And Yes SendInBlue, offers you better prices, good service, and quite good design features, however, the cons are telling me to run away from SendInBlue.