I keep reading posts like this one as considering replacing my Dart more really to try something new. Seeing that the cheaper DC pumps still taking a chance, guess will stay with the proven Dart (running 8+ years) a little longer.

I bought 3 DC12000's at the same time as FragitDan and we've had quite a bit of communication between us through out the ordeal. The failing controller of a friends unit, coupled with a series of unfortunate events, led to over $20K worth of damage in their home. RLSS has sent a Gen2 controller for all the pumps we bought. The event described above, turned out to be the straw that broke the camels back for them, and they've shut their tank down. I've taken one of my Gen1 controllers (which was still sitting BNIB since my build is so slow) and hooked it up to my friends DC12000 and it's powering my Lifereef Vs3-48 skimmer. The controller fan unit sucks and is noisy. The new Gen2 is probably close to 3X the size and is just a large heat sink. No active fan.

My original plan was to have 2 - DC12000's as my return pumps pushing 12' of head from my basement fish room to my 210 gal living room display, but I'm beginning to worry about having adequate flow. One of these days I will take it outside and test what they push at that head height.
I'm not quite ready to bail on them quite yet, but FragitDan is right when says customer service is horrendous.