I have been running a single ring on the front for most of my riding for nearly 15 years as I find it simpler and I don't get dropped chains. This has been fine for virtually all of my local riding even when I have been pretty unfit and recently while I have a knackered ankle. It is also handy for the days that I mess around on DH tracks.
However when I go further away to larger terrain my fitness/ankle hasn't been able to cope with the much larger climbs and as such I find myself walking a lot of the time. A granny ring would definitely help in this situation but would it get in the way the rest of the time?
My 9spd drivetrain is on its last legs so I am going to upgrade to 10spd when the time comes, I have a front shifter and mech in the spares draw so I don't need to worry about the extra cost. I also have a dropper post with remote so will that get in the way of a front mech?
Finally I would still like some sort of chain retention, this is the bit that will add to my costs. I currently have a Gamut and it has been great I never get dropped chains. Is there a double chain device that will do the job nearly as well? Will these fancy thick/thin chainrings work as a 2x10 or just as a 1x10?