I had the DEQ2496 in my system for many years (2003 or so to 2009). A very feature packed unit I used with the behringer measuring Mic.
I never had a problem with overheating, but after four years the first unit croaked - no more display. At the price it is not a big loss, so I got a second one.
I manually smoothed the auto eq afterwards to prevent to steep dips and rises. It did a nice job in a room that was quite well damped (books on the wall behind the listening pposition).
I was able to EQ Kef Calinda (sounds un-equed like a piece of crap with total imbalanced sound reproduction) to sound like a kef104/2 - quite a feat. I eventually got rid of the DEQ as the kef 104/2 in my room sounded the same with eq (subwoofer assisted of course) as without it, so no sense to keep it in. The DCX did a fine job until I switched to the hypes AS 2.100 with a build in DSP and set my filters there.