Need SMTP Solution for sending e-mails!

Hi! I have been reading for some days the forum and find several persons that build smtps solutions with for example:
-Interspire + PowerMTA
-Sendblaster + Postfix
-And so on

Also, there are other solutions you can use like sendgrid, mailchip, etc. with your own client side mail sender. This kind of solution i already used it on the past.

The main problem i have, is that i'm offering the service to other persons/companies and sometimes their mailing databases are not the best. So with the second option (sendgrid, mailchimp, etc) i will surely start having problems with the sending reputation. I often use programs to check the emails databases but most of them are not 100% accurate, the only way to know 100% that a email is working is to send a real e-mail to that account and see if any replies comes back.

So being said that i'm on the time to decide what is the best way to accomplish this:
1) Get the best inbox rate possible
2) Avoid having issue with smtp service in case database has not been properly generated and affect the reputation of the sending IP (Maybe this is accomplish with IP rotation right?)
3) Have a good html message generator from the client side mail sender (Since i'm not a HTML designer)
4) Be able to get good tracking information of the emails i send.

Note: The amount of emails i send montly can vary from 20K-30K to 100K-120K for example.

Thanks for everyone who takes the time to read this on this great community!

Regards!

Hi! Is there anyone with experience on the subject, i would really like some help on this...also looking for someone who offer this kind of service or implement the solution to complete this task!

Thanks!

Capula, 100% inbox not possible

Hi! Yes i know, but to make sure that all the possible configurations to avoid this are done. Then if you go to spam folder, it just bad luck...not a wrong configuration from your smtp server.

Thanks!

SMTPs have reputations across the internet. You can send off your desktop, but your personal IP will have no reputation. Also your ISP might take notice of too much volume. And with too many complaints your personal IP will be added to spam databases, further mailings from that IP will be labeled spam.
Services like you mention work to keep their reputations good, to improve their inbox rate. You can try to piggy back off the reputation of Gmail, Yahoo, etc other free SMTP providers using software like 1and1mail or mailking, that send through accounts registered at Gmail, yahoo, etc. Then you need to throttle send rates over time, possibly rotate IPs, and change the composition of the message to keep it unique. Gmail lets you send only 8 messages in sequence if they're identical before the account will block that particular message.
Sorry if you know this. That's all I know of it.

Thanks blkelvis! On the past i used to send emails with a software call Gmail Inferno that used gmail smtp, but it was full of issues and right now it was discontinued. I don't know what is best, to use a free smtp provider as you mentioned (I know that the issue there is the amount of accounts needed to send high amount of emails and also the account blocks) or ask someone to configure a smtp solution with all the setting properly as i mentioned on the first message.

Thanks for the piece of advise!