Sucuri's free scan only sees what a browser sees, by its own docs. WP Freedom reads the files on the server, keeps the evidence and proves the cleanup worked.
A host suspension notice and a clean result from a free online scanner can both be true. Sucuri's own documentation says SiteCheck is a remote scanner that cannot read the files on your server, so a backdoor in the uploads folder or a core file that shows nothing in the browser will not appear. The host is looking at the server. WP Freedom does the same, from inside WordPress. It checks core files against the official checksums, looks for executable files in uploads and changes nothing explains, then saves each item before it removes or replaces it.
Sucuri is the stronger choice if you want a managed service, with a firewall that filters traffic before it reaches your server and a team that cleans the site as often as needed. Sucuri says its plans cover one site each. WP Freedom suits the owner or developer who is doing the cleanup and wants to see the server side files, keep the evidence and confirm with a rescan that the site is clean.