My primary concern is my learning curve with a new host’s cPanel and their support quickness, especially by chat. The client would be paying hosting fees but I would be spending my time dealing with their host. The client is a non-profit whose cause I believe in. I would be glad to donate my SG commission should they host with SG.
From a developers stand point, although having root access to the server we will be using to host the website is not required, it is most certainly preferred. Having root access gives us complete control over the environment we are building the website on and eliminates the need for having to wait on a 3rd party. In addition, having complete control over the environment saves us from having to deal with a web host that is blaming the developer for poor website performance or sometimes pushing unnecessary upgrades onto our client. The list truly goes on and on as to why we prefer to keep our web hosting “in house”.
With that being said, your situation is a little different, but somewhat similar in that by working with a web host you are not familiar with, you are dealing with an unknown (which can come back to bite you in the rear). My suggestion would be if you are truly more comfortable working with siteground, feel free to give your client the honest reasons why. A good way to present this is “I am ok with using Bluehost if you choose, however if you would like for me to provide ongoing support for your website, it would make my life easier if we go with siteground).
Truth be told, in the world of the individual freelancer you are simply just going to have to get used to working on various different platforms until you get tired (or busy enough) to invest in your own web hosting operation. Even then, you’ll still get the occasional client who will insist on going with thier vanilla flavored web host (godaddy, hostgator..ect).