The big things to look for in portable saws are "will it take a full dado blade stack", "are the miter slots the full standard dimension of 3/4 X 3/8", and "is the arbor shaft 5/8" diameter"? Most won't take a full dado stack, and few have accurate standard 3/4 X 3/8 miter slots, although some are close, but not a proper fit for a standard miter gauge bar.
Most of these saws use a high speed drill type motor that screams when it's running and none of these saws seem to have any really good saw dust control. It is possible to cut dados with routers, so having dado capability isn't a deal breaker, but it's a nice feature. A Ryobi BT-3000 saw that I once used would take about a half stack of dado blades, so 3/8" dados were possible with it, but it sure did scream because of the type motor in it. It didn't even have a miter slot, so commonly available jigs couldn't be used on it without extensive modification. I've heard that the present DeWalt saws have inaccurately sized miter slots, so again, available jigs won't work well on them.
Older "Contractor Saws" have motors hanging out the back and these motors are much quieter induction motors with better speed control at the proper rated blade speeds, but none seem to have any good method of controlling saw dust issues, but all of these that I've seen can take a full dado blade stack. Be careful to avoid the pre 1950's saws with 1/2" arbor sizes, because finding blades for them is now nearly impossible. You can get bushings to make 5/8 arbor blades work, but they are hard to keep in place when changing blades and get lost in the saw dust easily.
The older Delta Contractor Saws use a specially made motor that produces 1.5 hp on 120 volt power to keep it's running current rating below the common 15 amp rating of construction site circuit power, but will produce a full 2 hp when connected to 240 volt power. All have 5/8" arbors and can take full dado stacks. The Delta 34-444 model that I found for my son has proven to be every bit as accurate and capable as my Unisaw once we cleaned it up and calibrated it. Any one of the 34-4__ series seems to be the same saw with tiny year to year changes. I think they incremented the model number each year that they were in production, so any one of them should prove to be a good and accurate saw once cleaned up and calibrated.
I have no experience with the newer Bosch Contractor Type Portable saws, but other's recommendations on them would have me leaning toward one of them if I wanted to buy a new portable saw. The included folding stand is a nice feature in this saw too.
Central North Carolina