I had a Dewalt 12 inch and sold it because the blade always deflected so angles weren't ever accurate. I replace it with what I considder the best sliding miter, the 10 inch Bosch. Amazing accuracy right out of the box. However, you MUST use either an engineer's square or preferably, a Wixey digital angle finder to make certain that blade angle is correct. The one I have is about 5 years old and remains a great tool.
It is a compound sliding miter, and it spits out vast amounts of sawdust. I made a framework over it, on which hangs a shower curtain, gathered at the bottom and taped tight to a 4 inch dust collection hose. Greatly reduces stray sawdust. Also learned to pull the saw toward me to make a scoring cut, then push it back through for the bulk of the cut. This provides a channel for sawdust to go back into the shower curtain collector. I am thinking of using some sheet aluminum to extend the dust collection port down closer to the base to clear out more sawdust through the 2.5 inch port.
I'm very happy with every Bosch tool I've purchased so far.
I think the space saving of the newer models without the rails is a nice thing, but for the money, the rail model is unbeatable. No longer much of a DeWalt fan. You get what you pay for. Hope that gives you want you want to know. Accuracy, smooth operation
The more I do, the less I accomplish.