Mg for mg I'd conseder EQ to be the stronger of the two and also the least likely to cause side effects. Deca has a progestegenic nature which means that, although it doesn't aromatize as well as test it can still have many of the same side effects. On the other hand deca will also cause alot of the "water bloat" associated with aromatizing compounds and so the gains while on cycle are better than for EQ.
The other side of the story is that EQ has some unique properties that make it a useful steroid. It increases appetite (always a bonus when going for gains in lean muscle mass) and it increases red blood cell production giving a tight vascular look to those who take it.
In the end I'd say EQ is the better compound. But that's just my opinion, many others would disaggree.