All very good questions. Personally, I have an Animas Ping and I like it more and more each day. I have been hoked up for nearly a year, and have had great control, as opposed to MDI, for every day that I have been hooked up.
First, I use the food catalog rarely, but when I do use it, it is of a great help. The food catalog can be customized in your meter to help with the foods that you like to eat. I think once I memorized the carbs of the foods I eat regularly, I use it less, but it is very handy when I need it. It has saved a lot of highs and lows.
Second, with a pump, no matter who's pump, you need to test, test, test. I like the remote features fo the Animas and that is a partial reason that I bought it. I also like the colour screen for my old eyes, and the software that goes with the machine. This is not to say that MiniMed's software is bad, but I just liked the Diasend better.
Third, I'd like to have a Dexcom, but my insurance doesn't cover it. I guess that is about the same as being unavailable. Many will agree with your statement that Dexcom is the best one out there, but sorry, I have no experience with either Dexcom or Medrtonics. I can't really say anything bad about a Medtronic pump. They are a good pump. I didn't care at all for their sales rep or their pushy telemarketers; but that is me.
Four. I run Linux too. You will need Windows for the Diasend and Animas tracking software. These are separate programs, and the Diasend is internet based, so that you can share information with whomever you choose. The Animas software tracks your pump and meter data too, but does contained on your hard drive. I am not so sure of compatibility to Windows 8, but I am sure the software engineers will address this. It may be available for MAC as well, but I have no experience with MAC software or hardware.
I hope this helps. All the best with your choice.