QuickMail just works; it’s fairly affordable compared to competitors, and their tutorials are really good. That is what drew me in. Their tips are valuable and do work. Our email marketing has been quite aggressive.
We use MailChimp for newsletters.
Mailgun's incoming email API is awesome. We are really happy with it and we use it for a lot of domains for our customers.
Exact Online is a full bookkeeping suite. It’s specifically targeted for the Netherlands.
Moneybird is really good. They started out as an invoicing tool but expanded to do bookkeeping. They are by far the market leader, and make bookkeeping easy. They started in Holland but will expand into other markets soon.
I really like LastPass--I have been using for the longest time. We have accounts for all of our client portals so we manage hundreds of passwords. LastPass allows us to share credentials. They have a good browser plugin.