Rules of thumbs:
- There isn't any method that is 100% efficient and safe. It is just a matter of time before some crawlers implement a countermeasure to it.
- Methods that you can find by googling or mentioned on StackOverflow are likely no longer safe. (But still better than plain text.)
- Showing email address in an image is definitely not the way to go. Don't you see captcha has surrendered to text recognizer and moving away from text in image too?
- You are relatively safer if you implement your own algorithm because crawlers are less likely to spend their time implementing a hack just to harvest email addresses on a single site.
- Email address is loaded & rendered only after some user action, e.g. clicks or scrolls.
- Email address is only shown to authenticated users.
- If the email is meant for customer support, use a contact us form instead. (Add a captcha too if needed)