If you're not getting good results with the Lansky, you need to deal with whatever is causing you problems before going on to another sharpener. Most of the guided sharpeners work pretty similarly and if one doesn't work for you, the same problem will likely be encountered with others.
Here are some possible issues.
1. Maintaining heavy pressure during the sharpening process. While heavy pressure can be used for the early sharpening steps of a very dull knife when using a coarse grit stone, as the process continues, pressure needs to get much lighter. During finishing steps and fine grit stones, the pressure should be very light. Pressing hard on a nearly finished edge will roll it over and ruin it. To be clear, when I mention that it's acceptable to use heavy pressure in the beginning of the sharpening process, I'm not saying that heavy pressure is ever really a good thing, just acknowledging that there are times when it's not a terribly bad thing.
2. Not completing the early steps when a coarse stone is used to grind in a proper edge bevel. The key to this step is feeling the "burr" along the edge. You can feel it with a fingernail on the OPPOSITE side of the edge from the side being sharpened. The burr should be present along the entire edge before turning the knife over to do the other bevel. Then, once the burr is present along the edge again from sharpening the other side, it's acceptable to progress to a finer grit stone and lighter pressure.
3. Ruined stones. If the sharpener uses diamond stones and they have been used with heavy pressure, the diamonds, which are very sharp, and very hard, but also very brittle, will be broken off quickly leaving a very fine grit which may be insufficient to sharpen a dull edge in a reasonable amount of time.