I bought a used Core Fusion 1 in August of 2015. Rode it up until the day I broke it riding in the stormfront of Hurricane Irma a few weeks ago.
It was a very well sorted, versatile freeride board. About as light as a Slingshot Widowmaker my friend had, but more more grippy on the water. Handled chop about as well as a Best Admiral, but was much lighter. Loaded well, good pop, but the footpads were subpar. Tore a strap free, so got the Union pads about a year and a half into ownership. Those seem much more durable strap wise, but I tore one of the footpads doing a darkslide a month into ownership. Would love to use different pads (Nobile seems to do a lovely job), but Core has unique bolt spacing.
Cracked the upper deck of the board (No idea how) doing a fairly calm jumping session. Was a little underpowered on my 9m, went out with a intact board, came back after it felt a little spongy. Cracked through the deck beneath a footpad. Bottom surface is fine, just the upper deck cracked clean along the width of the board.
I weight about 85-90 kg depending on my mood, and I do not wail on my gear. To date, the Core is the only think I have broken. Maybe it saw a rough life before me, maybe I mishandled it somehow.
Ride a Crazyfly Bulldozer now. Handls chop about 75% as well, pops about 50% better, feels more solid, mildly heavier. Made with aramid fibers. Not sure if that is a good thing, but it sounds good.
Basically, I was a huge fan of the Core board, but if I had cash, I would order a custom Carved with some more reinforcements. I would take the same board, sacrifice the light weight to get the durability back.