If you've got a bunch Spektrum receivers already I'd go for the M11 with the spektrum module. You ought to be able to pick up an M11 for a decent rate as it is the "old" model.
They are both very capable radios and if you can live with the weight of the M11 it really is a fine piece of kit. I've got one and use it with a Spektrum module and it has never let me down. You can stick virtually any small 3S lipo into it to reduce the weight if you want to as well. I use a 1450mah 3S lipo in mine. It weighs a bit less and still last me a good 5-7 hours on one charge.
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