Sendinblue few question

Hi! we install plugin (3.7) we don't have errors, but...

Few questions:
1.  "Automatic synchronization" - how this is work?
1a) It's change client status sendinblue <> Nopcommerce or only sendinblue < nopcommerce?
1b) If our CLient resign from our newsletter in sendinblue is nopcommerce receive this information and change "checkbox" to inactive?
1c) if our client resign from newsletter on nopcommerce page is this information are send to sendinblue?
1d) How often this plugin make synchronization?
2. Is this plugin export only active contacts? or all? If all, how we can add filtr and use only "active users"?


Thx for help!

PS Maybe someone use sendinblue and mailchimp and can compare which one is best? We choose sendinblue because pricing plan are better but...?

We using Mailchimp for 8 years now. Last year I decide save some money and move to SendingInBlue. its a little cheaper. Unfortunate SendingInBlue have 20% click rate in campaigns. We have large list over 6000 subscribers and click rate its usually around 15%. SendingInBlue disable our account. Than you have to make phone call to support and they have to make acceptation. After three time they disable our account for good. SendingInBlue is France company and support for US its not relay friendly.
So after all those aggravation I move back to Mailchimp.
Mailchimp its little more money but its easier create or modified template for newsletter and have click thru rate standards for retail store 15%.
On the other end plugin for Mailchimp synchronization not working 100% correctly.

Yeap! we have the same... we bought dedicated IP, but now i don't know if i click in nopcommerce "automaticated update'ing", what it do?

1. Is this sending information both side? sendinblue >< nopcommerce or only Nopcommerce> sendinblue...

2. Is someoune unsubcribe in sendinblue is nopcommerce receive this information? and unsubscribe record also?
3. How often this synchronization is working?