I'm using it for a few months now. Previously sugawa for 4yrs.
I bought sincero because sugawa heating tube got some problem n sincero gave a good price for trade in. Both also standard size and it's just plug n play in my cabinet.
Function wise both are the same, and for quality, I guess they are still the same. As for the glass discoloration like what 6216 mentioned, yes, both also have the same problem. I tried to use dishwasher to clean it, but nothing comes off. Sincero said better to use jif to clean it.
For my observation so far, both model provide similar user experience for me.