If you're looking for a low-cost solution to serve the same website to users in both continents then https://www.cloudflare.com/ will help keep delays to a minimum. From CloudFlare's own website:
CloudFlare operates out of 30 data centers around the world. Our CDN
automatically caches your static files at our edge nodes so these
files are stored closer to your visitors while delivering your dynamic
content directly from your web server. CloudFlare then uses a
technology called Anycast to route your visitors to the nearest data
center. The result is that your website, on average, loads twice as
fast for your visitors regardless of where they are located.
They even offer a free tier that will probably suit your needs. This way you can host the origin server wherever is closest to you or whichever side of the Atlantic has more visitors.
(I'm not affiliated with CloudFlare in any way.)
eu.example.com
andus.example.com
can have lots of advantages.