They can provide a great and fast interface for users, but...
Is just you, or is it going to be impossible for Google to index a single page site?
If you view the source in your SPA you won't see the content (and neither will Google).
$("#important-info").html("This is what Google needs to read.");
How are you going to get Google to see this?
<div id="important-info">This is what Google needs to read.</div>
You know better than to try to write the same code twice.
The single page app was going to mean you had fewer server problems. Instead, it sounds like it is going to introduce a new one. PhantomJS is fixing one problem, but leaving you with a new one.
For all this pain around SEO, you can't ignore the benefits of making a single page web app. The clean back-end restful interface. The super-fast load times as the user navigates from "page" to "page". All the logic is in one place instead of split (or even duplicated) across both the client and server.
The single page setup really solved most of your problems. Imagine if you could make the SEO problem just go away. You can't ignore Google. At the same time, you can't let making your pages crawlable become a distraction. You have a core product to build, and that is where you need to focus.
We fetch all your pages and pre-render them with a headless browser. You don't have to worry about running servers or setting up PhantomJS. This process is transparent to you.
You will have to do a little configuration to properly proxy the file from BromBone to the Google-bot. It's actually really easy and only needs to be done once. In most cases, we can provide the exact code you need to paste into your config file. We'll be able to guide you through the one-time setup process and then you can forget about it.