Advice Needed: Finally starting my UV/Digital Library

[Jonkai]

Hello All,
I have been a Blu-ray collector (and hoarder) for a few years now. There are a number of titles that I have yet to open, mostly the ones with nicer packaging and the digital copies included. That being said I have never redeemed one of those codes. I want to start creating my digital catalog now.

I need advice on what is the best service to use for having the most accessible digital library that includes movies from every studio and distributor (Disney, Sony, Universal, etc). Maybe I might be confusing my terms and names, but I guess where is the best place to start redeeming my movies? Vudu, Flixter, iTunes? Any help or clarification is appreciated.