I love all of the first hand experience with this grinder in the thread... it's comical.
I have the 9" and the 7" from HF and both have held up great for 2+ years so far. They are dedicated to concrete/block cutting, so they see some hard use. It was used to cut about 15ft of curb and did it like a champ. I do blow the concrete dust out regularly though (as with all my tools) because I am not trying to be stupid and break it. No complaints about it at all.
If this will be used in a professional environment, then I'd get Matebo. If you will use it around the house regularly and want to save some cash, then I'd get the HF.
Edit: I cannot however, recommend the HF worm drive saw... it's terrible.