Even though the 1050ma version technically outputs 1050ma, it is generally safe to run LEDs that are rated at 1000ma, such as the Luxeon ES Royal Blue, and Luxeon Whites. We've been doing this for years without adverse effect, and LEDs show no sign of degradation.
On a side note, the internals of this driver are thermally potted, meaning it is well built and has no hotspots. During our testing, we cracked one of these open to find that it was surprisingly well built and designed for safe operation.
The ONLY downside that we could find is that it is not controllable, other than on/off.
