I've shot Canon EF glass for a number of years. Recently purchased a BMPCC after researching and talking with people about them for about six months. Of course it depends on what you're shooting with the BMPCC, but I'd say if you have good lenses that you know and love that the meta-bones seems to be the way to go. I've rented a number of the different micro 4/3rds lenses and most are underwhelming in comparison to the EF lenses I own and use. (and there is a price and build quality difference to consider certainly.) Personally I've decide to go the route of finding quality older lenses and go the basic adapter route with them.
You're always going to need location sound. If you were to ADR (Automatic Dialogue Replacement) ie. re-record the dialogue in post, then you have to mix it with the location sound to get something that sounds pleasantly natural.
Sound is always going to be difficult to tackle in film making, but I'd suggest at least investing in a basic mic of some kind. You can spend a lot of time making your shots look good, but if no one wants to listen to what's being said, it's going to be hard to get people to watch, let along enjoy your film.
Even a very basic wired lav mic connected to something like the Zoom H1 (there are cheaper options) and hidden on the actor will allow you to have some good direct sound. You're going to have to sync it in post most likely. Sound is an important part of film so don't over look it in regards to time or investment.
I think Japan hosting the 2020 Olympic games has been helping to push the R&D of a lot of cutting edge sensors from companies like Sony, and hopefully Canon. They already intend to record the games (not necessarily broadcast) them in 8K so having things like high FPS for 4K by that time is probably something they expect to have in the market by that time. Should look amazing.
It's a good that you're asking these questions, but you're asking for people with a lot of knowledge and experience to take the time and provide you with insight for your purchase; it first requires some input from you in order to know what is relevant to you.
It would be very helpful to know what you intend to film with it? (Features, docs, corporate?)
What your previous experience shooting has been?
Do you intend to edit or only shoot? (You need to have the processing power and storage capability if you want to edit all those beautiful pieces of footage.)
Where are you located (generally)? If you're in Europe there are going to be different options than if you're in the US or Australia.
Hope this helps get you some responses to help you in your purchase decision.
I've tried a few including:
ToonBoon Studio (Ok, but felt like it was still more for Flash type animations)
Frame Forge - Good for someone who really wants to focus on Storyboarding, but not if you're just trying to get things mocked up to show a DP.
I've been using Google Sketchup for a few years now mainly because I can download a model of pretty much anything, type of person/animal, vehicle, or building I need. There are a ton of models (almost all of IKEA's furniture is there) so it's very quick to put together a home interior and put a camera in. I export out either the stills or short videos to an NLE and cut an animatic for clients or DP's to see.
Can take a day to get your head into how to get everything positioned and move the cameras around, but once you've got it down, you can move pretty quickly and produce a lot of storyboard content. And it's free.
What kind of adapter are you using for your Canon lenses?