I've been idly playing with PredictionIO for this in the past. It works quite well, although I've never put it into production.
It's open source
It has pretty amazing documentation
It's quite flexible
It's amazingly simple to work with. This is the code sample they provide:
cli = predictionio.Client("<my key>")
Here's IMdb importer, implemented in PHP. I did not test this, it might be outdated already; last updated 9 months ago (May 2013). I have been happy with IMdb recommendations, but you might have different experience. If you are not, after importing ratings to IMdb, you can easily import those to iCheckmovies (related blog post).
The data format for IMdb ...
I understand your question because I've been wanting to create a company / app solely to address this gap. There is nothing in existence currently that will directly fill your need with excellence I must say, although I'm sure eventually it will come. In the meantime, people are using the following primarily:
TL;DR: Use Qt or .NET, both frameworks will do the job for you! Personally, I recommend Qt over .NET, but that's based on my opinion.
You ask about performance and whether or not the frameworks you mentioned are capable to run your appliciation, so I want to give you some examples:
Qt (afaik not quick) is used by: Autodesk Maya, Modo, Nuke, Houdini ...
I am not an expert on FOSS recommender systems - I have used more than one to do Cross-Selling, but all of them built from scratch.
Recommendable does not appear to be applicable to your case. Recommendable sends the recommendation after the user has rated the current item. Since you are scoring the items in a way that doesn't involve user interaction, you ...
Listal creates recommendations by basically averaging out the votes of users you pick into a top list. It does find users with similar tastes for you but I usually just look for a favorite underrated movie and pick people from there. Listal definitely has an import and export function. "edit profile" -> the import tab is to the right. can take XML or ...