FusionPro VDP Creator (MAC/Windows) is a good VDP application to start with. It can process up to 350 records per minute, but can be less depending on the number of rules, variable elements etc in the VDP document. If speed is a prerequisite, then the next level up is FusionPro Producer. It's a windows only server based solution, which includes up to 5 FusionPro Designer client licences (MAC/Windows). They can only output 1 record locally, but are designed to be used with the FusionPro server version. This means that the local computer isn't locked up processing hundreds/thousands of records and allows you to work on the next document or something else. If you're looking to have more than two FusionPro licences, then FusionPro Producer becomes an interesting option in terms of price.
Just note that the FusionPro VDP Creator plugin works mainly in Acrobat Professional to build your rules and elements. It's only used in InDesign to mark elements in the design, which you want to be variable. Then you export the layout/design from InDesign via the FusionPro plugin out to Acrobat where you start building the VDP document. From my own experience with customers, they don't always have access to the original InDesign file, just the PDF. So, that for me is an advantage.
You can link it to Fusionpro Expressions, which is a cost add on, where you can design personalised pictures (there are prebuilt designs within Expressions and prebuilt templates that you can buy) ie. have someone's name in the sand or on a bottle of wine etc.
The FusionPro forum is excellent in my experience. If you have a question, you can normally find someone else who has asked a similar question. If not, create an account and post your question. There are a couple of FusionPro developers on there and hundreds more who have been using FusionPro for years.
FYI. My company sells FusionPro in Europe. The other VDP application that we sell, is PrintShop Mail, which is a dedicated VDP application (not a plugin). The main differences are that you can use XML directly as data input and you have an option to create variable email. It's more expensive, but then you don't have to own/buy Adobe Acrobat/InDesign. It can be upgraded with Power Packs to handle more data for performance and you have the option to upgrade to PlanetPress, which is a workflow solution ie. create variable output to web, email, print and automate processes ie. the web output has a link, which uses PlanetPress to initiate an action, like personalised invoice, invitation etc. It's a swiss army knife, but usually requires consultancy to build a workflow.
Hope that helps!