Slowdowns are natural for any VPN because the signal needs to travel more - from you to the VPN server, and then to the data you request. The closer you are to the VPN server, the shorter is the way, and the lower is the speed loss. So please use the countries nearest to yours, and you will have the highest speed possible.
As for the new tab opening: we inform free users about our current promotions. Many value this as an opportunity to get our Premium service with a good discount. This happens once per promotion. To stop this information, you can turn on "Don't show promo offers" in the extension settings.

Yes, some anti-viruses treat our domains wrong. We can assure you that Browsec has no viruses or other threats, so you can just whitelist Browsec in your anti-virus settings. Also, please contact us at support@browsec.com or here - https://browsec.com/en/contact_us - and name this anti-virus. We would like to contact them and resolve this issue.

Hello, please contact us at support@browsec.com or here: https://browsec.com/en/contact_us. We will be happy to help you start using Browsec.

Hi, we do our best to provide free service with acceptable speed. If you notice sufficient slowdowns or drops, please report this at support@browsec.com. We'll do our best to help you!
As for the country change: we offer the following virtual locations for free: Netherlands, Singapore, United Kingdom, United States. The other locations are available in our Premium plan.