I opted for the the lifetime option Level 3 for 15,000 contacts and 'unlimted' emails.
This gives you the basic service. (The marketing material does not explain what you would get if you went for Level 5)
Set-up and account verification is straight-forward (If you want to use your own email address, you do need to update your DNS server with sendfox credentials and have this verified).
Social media integration is great.
If you have much on social media/blogs etc the the AI prepares automated emails for you.

The basic service works really well.
There is a very basic email editor with just the essentials.
The sendfox database only handles Email, First Name, Last Name. So you need to edit your database outside sendfox.
It is immediatly GDPR compliant when you choose that option at the start.
The customer service (email) is excellent! Response is quick and to the point.
The sendfox watermark is actuall 'elegant' and does not really disturb.
The campaign management on the basic service has only timings to send emails every 5 minutes. Unclear if the the subscription service allows for more.

Here is what you need to know:
-Account warm-up: It will take some time until you can send emails to large lists. The warm-up pattern is algo-driven and I am yet unsure of the credentials.
-You need a monthly subscription (of USD 10) for a better html editior.
- I assume you need the above monthly subscription for a better database editor, too.

All in all I am very happy with this email marketing product.