I don't have an apex, but am kind of leaning the same way as Mortie. Once I have a sumped tank in the (more distant now that I like) future, I was thinking about apex+trident. It would be nice, but only nice, and I'm not sure if it's worth the coin.
First, it seems to me that Trident is only useful if you dose the three (or four or whatever) part formula of your choice. You can watch things by trident and hand dose I suppose, but if you're doing this you probably want a doser. You can go ~$400 for a decent three pump doser and container, but it seems to me that if you have trident it doesn't make sense not to have the DOS. Since three part needs two sets of pumps, you're now out $500 (trident) and another $600 (DOS); maybe another $300 (DDR, though that might be a bit of a luxury.
Thus, all the stuff around trident will cost (new price) $1100-$1400; $1000 more than the basic dosing setup (not even counting the apex, which I've become less enamored with the more I think of it compared to cheaper, single item manufacturer automation systems from Coralvue, Ecotech, Kessil, etc.). Probably worth it for a large system, especially if you like expensive name corals. But for the average (40-80 gal, 3-4") aquarium, with maybe the occasional $50+ coral and the remainder in $15-50 livestock (maybe $400 in livestock total), with daily dosing requirements maybe measured from 1-20mL per additive, that's a heck of a difference.