I have an Aleko gate opener on my obs in the desert. (Same desert area as Charles). Works fine.
Beware, though that it takes some thought to get it installed right.
It is supposed to be mounted with the rack facing down, and the gear on the motor vertical, its cogs meeting the downward facing rack. The motor housing should be vertical. In fact, I think everybody I know has the rack sideways, and the motor mounted horizontally (instead of vertical). Works fine.
Mounted vertically, with the rack above the gear, and the weight of the gate holding the cogs together, there is no problem. That is how they are designed to run. The design forces the cogs of the rack and the gear to intermesh. However, our installations are horizontal. And remember, for most of us, the roofs can slide slightly side to side. So, several of us have had a problem with the rack and gear separating. In this state, the motor will turn, and the gear will of course turn, but since the cogs are not intermeshed with those of the rack, the roof will not move. So, be sure you do not have too much sideways movement, and be sure your rack is adjusted fairly close to the gear.
One other thing, I think we have noticed...….Extend the rack well past the farthest it will ever be expected to move the roof. (Well past means at least to the next anchoring screw.) That is, have rack sticking out further than what you thought was the end point of travel. This extra bit assures that you will have further reinforcement past the point of furthest travel. If you do not have this, the entire force of the gear/rack interface will be on one screw that holds your rack to the roof. (Or even worse, cantilevered past that last screw!!!) That screw will loosen. If instead, you have additional fastener further along the ling, the pressure is distributed more equally, and you have less chance of separation between the rack and gear.
Note, These things are made to sit outside in the rain and snow and all sorts of evil things. They are, after all, gate openers. But, I always felt sorry for them, since they were designed to sit vertically, and we have them horizontally, with the gears and stuff facing up into the hot sun, and falling sand and dust. So, I built a little extension of my roof that, when the roof is closed, covers the motor and gear. It should be said that while we have all said we thought about something falling into the gears since they are mounted sideways instead of as designed, .....nobody to my knowledge has ever had a problem. Even those without that little roof extension to cover the mechanism.
Or maybe not. I am just trying to relate what I think I have seen in the eight to ten installations we have at our site.