Eq.
If you are happy with EQ, my opinion would be to stick with that. Deca is slighlty stronger but is also more suppresive to the HPTA and bros can run into progesterone related sides. In an overall comparison, sticking to EQ will be fine over the slightly better gains (and sides) you may get from the deca. Unless you have joint issues which deca will help with, i say stick to the EQ since you are happy with it (you can also hit the EQ up to 600mgs/week if you haven't already, I personally see diminishing gains past 600mgs per/week and my experiment with 800mgs/week of EQ found it not be much better than 600mgs/week). Plus the anti-estros you might be taking will work with both the test and the EQ, but won't work possible deca related progesterone sides. Not to sound like a broken record, but since you have had good experience with EQ why worth the risk of deca sides over possible slight increase in gains (if you weren't happy with EQ then i would be all for experimenting, but if it ain't broke why try to fix it).