Miter Saw stands are generally categorized into 4 types of support systems for miter saws:
2) fixed or portable tables with the saw bolted into place;
3) hybrids of rails and tables and finally
4) part kits that assemble around a large 2x wood core.
All of them will help you to work better. Selecting the right one for you requires first an understanding of the type of work you do, then the degree of the portability you need, your budget and finally a lot of personal choice.
A COMPARISON OF JOB SITE MITER SAW STANDS is an article that I wrote in the summer of 2011 but it never got published. So rather than just letting it sit in my computer -- here it is in PDF format.
This chart concentrates on saw supports for site work. In a workshop it is far better to build the saw into a bench with wing supports and don't buy any of these -- unless you need to go in and out with your saw.
If you have a smal shop, place the saw at least 8 feet from one side with a permenant leveled work surface to support wood for the saw, and then a temporary support on the other end that can be used only when needed. Don't forget that the support table for a miter saw or a radial arm saw doesn't need a lot of head room - so that support table can be the top of low cabinet storage space, and upper cabinets can be only several inches above the support surface. No space wasted.
I saw one garage arrangement where that second support was actually placed outside of the garage on the driveway and a small slot hole in the wall was used to push wood through -- that's manimum use of space!
For a complete series of videos on using miter saws, follow this link to the Learning Curve.