I have had the redarc dc-dc charger, the 50a model for about a year and a half. Its been trouble free, you dont even think about it. The only limitation Ive seen is that combined with a BMS equipped lifepo4, if the battery runs down and shuts down discharge, the system is dead until you introduce 12v+ between the two. (Obvious an issue for any "smart" system, to be dumb like this)I dislike the renogy DC-DC that also includes MPPT solar as it's very limited. I'm of the opinion that they should be separate devices.
DC-DC charger between Sienna 12V and House battery and dedicated solar MPPT to house battery.
Silly me thought I could just start the car and once juice was flowing everything would work. I now carry a long cable with an anderson plug at one end that hooks to the main battery (to a fused anderson plug) and alligator clips on the other.
The redarc unit does have solar input, doesnt have to be used. I recently hooked up 2 100w panels to it, runs my National Luna freezer full time dont even have to start it.