Is anyone an expert in email services?

I used Feedburner then migrated to Feedblitz. Feedblitz has great metrics but my email looks different on every service and I’m losing readers!
I need either help with Feedblitz or to move – once again – to a service that will remain solid across all email systems.
I’d like to hire someone to understand my needs, suggest the best service and implement that service.
Help!
Thank you.
Horseandman.com