First, +1 to Leigh's recommendation not to skimp on developer volume. This applies to any method, trays or tanks.
Chris, the slosher keeps the sheets separated from one another so there is no sticking together. No presoak required. Sloshers can be excellent alternatives to tray shuffling if you don't need to develop many sheets at one time. Essentially a slosher is an attempt to do two things:
1) Combine the benefits of single sheet tray processing (pretty much the easiest way to get good uniformity and eliminate the risk of scratching) with the ability to do more than one sheet at a time
2) Allow for the option of truly intermittent or minimal agitation, vs shuffling where there is always some movement of the sheets and developer as long as you are shuffling
It can sometimes be easier to get uniform development with a slosher than shuffling because by lifting and dropping corners or sides of the tray you can get very good random agitation, which is why single sheet tray processing works so well.
The limitation with a slosher is the number of sheets that can be done at the same time. With practice some people can shuffle 8-12 sheets effectively. With a slosher you are limited by the surface area of the bottom of the tray. For example a typical slosher for an 11x14 tray holds six sheets, and in fact that is really a bit too tight if you want to maximize the probability of getting uniform development because ideally you don't want the sheets to close to the sides of the tray. A better slosher does 4 4x5 sheets in an 11x14 tray, or if you can do with lower volume processing (like me), 2 sheets in an 8x10 tray.
The best sloshers allow the solution to move around relatively unrestricted, as would be the case when doing a single sheet in a tray. Therefore the best type of slosher is one that has the least amount of material/surface area separating the sheets. Many slosher designs have "walls" separating the sheets. There is no need for this. An excellent slosher can be as simple as a few small stainless steel wire baskets attached together. Plastic baskets are also excellent. It doesn't have to be pretty, just get the job done.
You can also construct one yourself. I'm attaching an example of the slosher I made this past weekend (my stainless wire slosher recently met an untimely end). It took a couple of hours and cost about $10 in materials (1 8x10 sheet of 1/8" acrylic from Home Depot, and some 1/8" acrylic dowel from the local hobby shop). A variety of alterations and/or simplifications to this example are possible.