I've had great success using the 360/720 method of upresing images to 360 or 720 ppi when the native resolution is below those marks. Up until now, I didn't have a camera that had high enough resolution to stray from that. However, now with the D800e, I'm finding when printing smaller prints, I'm well above even the 720ppi native resolution.
Is there a general 'rule of thumb' when this happens? Do you downres to 720, go with the native resolution (900+ for a 5x7) or is there another plateau to res-up to (1440?)?
With the quality of current printer drivers, I'd downsample to 720 PPI and let the printer chew on that. The downsampling will make sure you have the control over how much aliasing artifacting will be created. The printer drivers are more likely to use a simpeler (=because it's faster) downsampling algorithm that you can utilize, even though it might require you to take an extra processing step. In addition, it allows you to determine the amount of sharpening you want to use to compensate for output media losses (due to diffusion and such).
A program like Lightroom uses a relatively decent downsampling quality, but Photoshop doesn't. So the downsampling method will depend on which application fits best in your workflow.