Both will shoot very well but it comes down to the Ego 11 being a poppet and a DM13 being a spool valve. The markers will have a slight difference in shot quality. Do you want the high efficiency of a poppet with a loud, snappy shot? Or would you prefer less efficiency with a spool with a quiet, smooth shot? I recommend holding and shooting both before deciding. An empire axe is a cheaper alternative to both of those and while it is a poppet, it performs very similarly to a spool.
Paintball guns are for the majority - Personal preference nowadays.
I had both, but I sold the DM. In my opinion, the ego feels much better in the hands. Also, the ego is considerably smaller, but the DM shoots nicer. In the end, it comes down to personal preference. Try out the guns, then pick.
I prefer Planet Eclipse, and in the spool vs. poppet debate, I'll 9/10 choose a poppet.
I have not owned an Ego, although I did have a DM and currently own an Etha. I wasn't particularly impressed with the DM's reliability (refused to cycle below 30-degrees Fahrenheit), and I've always found poppet-valve markers to be more reliable and more able to Charlie Mike when things go badly inside them.