I've built three solar systems using the Morning Star 45amp MPPT controllers. None have failed, and they are very quick to respond to changes in solar output, eg, clouds coming and going.
They are also very flexible, allowing up to 150vdc input to be MPPT'd down to 12vdc. This has the benefit of using higher voltage panels and consequently, lower loss due to cable resistance from the panels to the controller. I'm currently running 600w of solar on my trailer @96vdc input to the controller.
On a side note, I also love the remote monitoring panel. My controller is right next to the batteries to again promote the shortest cable distance/lowest loss possible. The monitor is at the other end of my trailer by the front side access door.
This pics are a little dated, before I cleaned things up/finished--
Panels on the roof - 4 total
Batteries, Inverter and Solar controller (before I had mounted the monitor remotely)
Monitor's new home by the front access door
'15 F450, 30k Superhitch, 48" Supertruss, 19.5's, Torklift Fast Guns
'12 Eagle Cap 1160, 800watts solar, Tristar MPPT, Magnum Hybrid 3k Inverter
'15 Wells Cargo 24' Race Trailer, 600 watts Solar, TriStar MPPT, Xantrex 2kw inverter
'17 Can Am X3 XDS Turbo