I decided to build my own, and I achieved good reply rate with it.
It uses Google maps to find leads, you can specify location and categories. I got my first good results the other day. From 500 leads, I got 250 opens and 10 replies.
The email leads are checked with two different api's to ensure they are deliverable.
The emails are sent from pre warmed ip's, so you wont land in spam.
You can also upload your own leads.
You can personalized mail merge write once / use lead variables.
You also have automated follow ups, gradual sending, performance reporting, send in plain text if you want and schedule emails per leads timezone.
I find my prices very competitive compared to other tools.
If your product is B2B I highly recommend checking out my tool. It's a lot more affordable than other similar tools and it's also much more affordable than running ads.
Cheers