I've looked at them to use for my email/small web server and like their prices and features, but am not sure of the GDPR implications.
Currently I use a US cloud provider, and I'm in the US, and so am a controller or processor not established in the Union, and all my data processing takes place outside the Union. All my GDPR obligations, if any, are those that arise under the extraterritorial jurisdiction provision of Article 3(2).
If my server was hosted in the EU by an EU company, would that still be the case? Or would GDPR now apply via the in Union jurisdiction provision of Article 3(1)?
This Regulation applies to the processing of personal data of data subjects who are in the Union by a controller or processor not established in the Union, where the processing activities are related to:
a) the offering of goods or services, irrespective of whether a payment of the data subject is required, to such data subjects in the Union; or
b)the monitoring of their behaviour as far as their behaviour takes place within the Union.
So it basically says that the GDPR applies, I don't think that hosting in europe would change anything at all.
It can't actually accomplish that goal, because the EU doesn't have the jurisdiction for that.
For controllers and processors that are in the Union, GDPR applies to their processing of personal data of people regardless of where those people are or what entities they are citizens of.
So, for example, as a US citizen residing in the US who has never set foot within about 7000 km of Europe, but has bought things from vendors in the EU, those vendors need to obey GDPR when dealing with my data.
For controller and processors that are not in the Union, the EU lacks the authority to enforce such a broad requirement on them. Instead, the requirement is that if the person whose data you are processing is "in the Union" and you are offering goods and services to them or monitoring their behavior as far as their behavior takes place within the Union, GDPR applies.
(Whether or not they can actually enforce that is still an open question).
Putting this all together, if I'm in the US, with users in the US, but having my server in the EU makes me count as being in the EU for GDPR purposes, then I have to obey GDPR when dealing with US users. If having my server in the EU doesn't do this, so that for GDPR purposes I'm in the US, then GDPR does not apply to my dealings with people in the US.