Blades come in very different configurations and vary considerably in quality. MK makes good blades and they make "cheap" blades. A concrete blade is very different then a rock blade and very different from a asphalt blade. Some can be had for well under $100 and some will cost over $500. Once you use a high quality blade, the cost difference is easily made up in speed of cut and blade longevity.
I certainly understand this. In my MK 100 series tile/brick saw I use MK blades and they run me about $120 each. but if you keep them dressed they work for a long time. I am sure that the MK in question is a cheaper blade but for the amount of use it will see it could be a viable option.
I have the Makita saw picked it up for $850 including diamond blade & 4.5" angle grinder.
Runs like a champ - used it to make some holes in my basement for footings thread here
Also on the pool demo project although the volvo backhoe mounted hydraulic hammer was more impressive.
Tip - don't run the diamond saw blade in reverse, it may ruin it. A buddy re mounted it after using an abrasive cut off blade to cut rebar. It don't cut like it used to