I've been looking at various sliders for a while but keep going back to the SliderPLUS models from Edelkrone. This slider offers about twice the length of camera travel as other sliders of the same size, thanks to its retracting rails. Take a look at this quick illustration to see what I mean.
Available in six sizes, the smallest (which, at 3.3 pounds, fits neatly into a backpack) provides about 1.3 feet of camera travel when mounted on a tripod and supports up to 17 pounds. The PRO Xlarge weighs about 5 pounds, delivers camera travel of about 2.9 feet when mounted on a tripod and supports up to 22 pounds. The highest carrying capacity, 30 pounds, is available with the PRO Medium.
Constructed of 100-percent CNC-machined aluminum parts, the SliderPLUS's temperature-tested aluminum rods and steel non-frictions ball bearings are designed for smooth movements throughout.
To really make the SliderPLUS (and your work) sing, add on one or more accessories such as a Flex Tilt Head, a Target Module that pans automatically and my favorite, the Action Module. The latter can be used with the Target Module but its strength lies in the Action Module's different modes.
For example, you can program the wizard to record a slide, including start and stop points as well as average speed of the slide, so you can run the same movement over again (with manual override if/when necessary). You can also set it up in Loop Mode while modifying speed and acceleration. Other modes include Timelapse, Stop Motion and Macro. With Macro, super-slow slider speeds allow you to get just the right focus, even with shallow depth-of-field.
Prices for the SliderPLUS range from $500 to $1,000. Check out this video to get inspired and to see examples of just what the SliderPLUS can do.