The hybrid has only been out for a little over a year or year and a half. I can't remember exactly when it was released for the 980, which was where it started. I am thinking it was February/March of 2015.

There was one person that claimed a small leak, but never heard what happened with it.

You couldn't replace coolant on the old ones, so that answers that lot of questions. The new one looks to have a quick disconnect, so that will change things.

Havent seen anyone talk about failures from the hoses or the radiators, although the one that posted about a possible leak was at the hose/radiator junction.

As for single AIO'S vs Full system, the heat isn't shared with singular AIO's, so it would be much more controlled per system. With the new ones being expandable, the hest will be shared, and it one runs hot it will bring the other one up with it, but if one pump fails, it will be a reduction don't system. With a full system, usually there is only one, maybe two pumps, so if you only have one and it fails the whole system is down. If the AIO's are in singular setup and one fails, you can remove it without having to disassemble and drain everything in the loop. If they are paralleled, the quick disconnect will be great for removing a single gpu with minimal downtime.

Just a few thoughts, although I haven't had a Hybrid. I have been following them closely as they are interesting.