During testing of sparkpost we are getting into the inbox with gmail, yahoo and aol, but not with microsoft. We are getting an 8 on microsoft's bulk complaint level which AFAIK is associated with the IP used.
We are evaluating either switching to a dedicated IP or switching to another service provider on a shared IP.
One thing that puts us off a dedicated IP is the extra admin that would be involved in keeping the IP off blacklists. Some blogs also mention that you need a certain amount of traffic to maintain sender reputation (though they are vague on how much that might be - I guess because there are no hard and fast rules). Since a lot of the stuff on the web is not impartial and is based on different use cases and potentially out of date, I would appreciate some thoughts based on experience from people in a similar boat.
If you are on a dedicated IP, how many emails per month are you sending? Has monitoring your dedicated IP for blacklisting been an issue?
If you are on a shared IP (either on sparkpost or other servers) have you had trouble getting into microsoft inboxes or with the BCL? Thanks in advance for all your thoughts.