Siteground by far. I have been with them since 2014 and have never looked back. These guys are definitely one to go for, especially with their 24/7 instant support when needed.
I can recall one incident when I needed to upgrade my hosting because I landed on the first page of Reddit for an image and I got tonnes of traffic coming in which my current package with Siteground wouldn't be able to handle and I contacted support and got them to move my hosting to a bigger server which handled the workload.
If I didn't contact them and if they were slow to respond, I would have lost out on $70,000+ worth of e-commerce sales and 9,000 people joining an email list.
Ever since that one incident, I always recommend people go to them.