I'm a little late with this post but it might help someone next time.
[USER=679]@BillH[/USER] - here are a couple random thoughts that I don't think have been mentioned yet.
One easy was to document whether your CRM (or the CRM you are considering) is having deliverability issues is to look at their senderscore.org rating. Find the ip address from an email sent from the crm (it is in your email header), create a free account at SenderScore.org, and then plug the ip address in. It will show you how many spam traps the ip has sent to in the last 7 days as well as the sender's email reputation score. That gives you a rating to discuss with your CRM rep.
Rotating ip addresses doesn't work as email companies such as yahoo, gmail, etc., are looking at consistent good behavior from an ip when determining whether or not to deliver your email to the inbox.
If you should decide to switch CRMs, make sure you export your suppression list (list of bad emails/opt-outs) from your old CRM. Not all CRMs handle suppressions the same way. Some will disable an email address if it is bad so it can't be sent to, others maintain a suppression list so the email send goes out > caught by the suppression list > before it leaves the server. The later type of CRM are a problem as exporting your list gives you everyone and once you send from your new CRM, you'll inadvertently send a lot of bad emails which will hurt your sender reputation at the new CRM.
Ideally the CRMs need to do 2 things:
1. Give you access to reports that allow you to identify your customer engagement. If you've been sending emails to someone who hasn't opened an email from you in a year or so, it's safe to assume that you have their junk email address and your message is going into a yahoo account with 20,000 other unopened emails. Over the years, if you build up enough of these bad/low engagement emails and sprinkle in a dose of spam complaints, it results in a bad email reputation which then leads to email deliverability issues.
Being able to identify engagement would enable you to clean out the inactive/bad emails which will definitely help deliverability.
2. Give people an option to use a dedicated ip just for their account so they are not impacted by other sender reputations.
Other CRMs like salesforce, infusionsoft, automatically monitor your sender engagement and if your emails have opted-in, are getting opened/clicked, then you'll find your emails are getting sent from their servers with better IP reputations. Mailchimp does the same thing.
