I currently have a good sized agency. Looking for some GWS and Azure inboxes for my clients. Had a lot of issues in the past with providers, so I am a bit skeptical.
I have heard about:
inboxworld
mailscale
puzzleinboxes
endy inbox
any experience using these at mass scale.
We ran an experiment over fourteen months and just over 100k outbound messages and the result was the opposite of what I expected going in. My team had been religious about personalization with manually researched openers and LinkedIn comments before sending and the whole 10x10x10 routine that everyone preaches and we were sitting at around 4% positive replies which is fine but nothing to write home about.
So we ran a proper split where one sequence kept the heavy personalization at 15 messages per rep per day while another did light personalization at 60 per day with no timing rules and a third used the same light personalization but only sent on Tuesday through Thursday between 9:45am and 10:30am local time and only to accounts that had hit a trigger event in the last 30 days like a funding round or a new VP or a key hire.
The heavy personalization sequence pulled 4.1% positive replies which was about what we had been doing already while the light untimed sequence dropped to 1.8% which made sense since the messages were generic and not timed to anything. The light but trigger timed sequence pulled 7.6% even though the emails in it were objectively worse written than the heavily personalized ones which is the part that still confuses me a little.
What I think it means is that personalization is basically a tax you pay to make a message feel relevant whereas timing is the actual relevance because if someone just got promoted into the buyer seat two weeks ago then a generic message about their new pain point is already more personalized than any line about their dog could ever be.
We ended up killing the heavy personalization sequence entirely and the team now spends that time qualifying triggers instead and we are booking roughly 2.5x the meetings with the same headcount we had before.
Genuinely curious if anyone has gone deeper on personalization than we did because I dont actually know whether the curve flattens after a certain point or whether there is another step up waiting at the spent an hour per email tier that we never bothered to test.