I’ve used the DC448 plenty of times but not seen this install version before. It looks like a nice piece of kit, and I’m surprised it’s so much cheaper than the 448, which on paper looks pretty similar (and they do both appear to have PEQ on the inputs). I guess maybe the DP448 is such an industry-standard piece of kit that it can command the higher price? I would also imagine the DC1048 is not quite as ruggedly built as their more expensive touring range (the DC448 is built like a tank), being intended for the install market so might not take kindly to being bumped around, but as I said, I have no actual experience with it. Out of interest, how much is the DC1048?
The phoenix connectors are a minor pain in the arse but if the unit is going to stay in the same amp rack then a couple of hours spent with a soldering iron making up a few custom cables and a suitable I/O patch panel would be all that’s needed to integrate it into your rig.
If you’re looking to spend around the £1000 mark, have you checked out Xilica processors? Their XP4080 is around £800 and is 4-in/8-out. We use a couple for bi-amped monitor racks (running 4x bi-amp wedge mixes each) and I’ve been quite impressed (well they sound pretty good to me and they still work!).