I have both the Lansky and Sypderco sharpeners. I use the Spyderco a lot more often than the Lansky about a ratio of 40:1.
The Lansky is great for stone variety, angle selection, and consistancy (once set up). I have found the following problems with the Lansky, the rods need to be checked often for straightness if you stress them, the angle is only consistent on a short blade (need to move the clamp for longer blades), never get the same angle each set up, need to measure/calculate the angle to find what it really is, and the guide wears and is rather flimsy. A really sharp edge can be obtained with a bit of care.
The Spyderco has many advantages; easier to set up, longer/larger abrasives so that they can be used for fine filing or free hand sharpening (such as doing khukuri's, chizels and axes), and the angle is same with each set up. The disadvantage I have found with the Spyderco are, needs a courser abrasive it can take a really long time for some blades, more attention is required for good results, only 1 knife angle in the old model. Switching sides is when sharpening is a breeze with the Spyderco, not as easy with the Lansky.
Will