After a lengthy machining career I took a job in the quality control department of a major supplier of OEM automotive parts. A percentage of my job involves repairing and calibrating measuring equipment so I have lots of expensive equipment for calibrating and verifying gauges at my disposal. I'm far from being a gauge snob but have tested some of the off-brand items mentioned just to see if they measured up. I use the HF calipers as digital readouts on my Bridgeport spindles and on my lathe tail stock at home because they're cheap and it didn't bother me to chop them up to fit. Before modifying them I brought them into the lab just to see how good they were. Surprisingly, the outside measuring jaws were pretty good, impressive actually. The inside measuring jaws and the depth rod are kind of hit or miss as far as correlating with the OD jaws but are good enough for rough work. Internally, the electronics of the HF calipers are identical to an early model of Mitutoyo, it's the grinding of the inside jaws and the depth rod that isn't always correct. Off brand indicators have their place too, but only as a zero reference, never for actually measuring using the graduations on the dial. I consider Shars and SPI to be off-brand. For my money, anything Mitutoyo is a great deal for a good price.