In my experience Amazon SES is great if you only used it for transactional emails. If you start sending marketing emails you will soon find yourself being blocked by ISPs and email service providers. You will end up spending a considerable amount of time getting yourself unblocked. Some service providers will even block the domain name, so even switching the service won't help you. Everything will go to spam from that domain name.

I have built the tech for an ecommerce startup (https://www.article.com) from scratch. Using different services for transactional and marketing emails is probably one the best decision i made early on.

Pro Tip #1:

"Use a different domain name for the from address while sending out marketing emails"

For example if your primary domain is example.com. Use support@example.com as your from address in transactional emails. Use support@example-mail.com as your from address in your marketing emails. Off course forward all emails received by support@example-mail.com to support@example.com (Why? see Pro Tip #2).

Pro Tip #2:

"Never use fake emails like do-not-reply@example.com for the from address for any email you sent. Yes not even for marketing emails"

You will be surprised how many time customer just reply to emails they have received even if it is an unrelated marketing email. You will regularly see customers receiving a monthly newsletter and they will hit reply asking "Can you change the shipping address on my order?"