I'm looking for a comparison of SaaS websites that force email activation versus ones that do not. Similar to how some websites review a checkout process across multiple domains.
Any requirement to validate email will almost certainly see a huge-drop off in conversion from visitor to user.
Ask yourself why do I need to validate? If it's purely to send further marketing to account holders, then just bear in mind that only around 25% of emails for SaaS products are opened. Even fewer engaged with. So you may be cannibalising your sign-ups to gain little.
Further more I believe that users are far more likely to provide fake email addresses where they have issues of trust with your site. So perhaps instead of thinking about email validation, think instead of conveying how trust worthy you are, and making it clear that you won't bombard people with spam!
Hope this helps and good luck!
First ask who the user is? What lines of business are they in? If they're an enterprise user then email verification is accepted. If it's consumer they reduction of a barrier to entry is always wanted.