I just want to support what Fozzy has been saying. I've been using these things for years. Last place I worked, we spent almost $300 on a set of Mitutoyos, and everyone was always fighting over them. I got tired of it and ordered a half dozen of these, based on the set I bought for myself earlier.
They always read the same as the Mitutoyos, but were just a shade lower in quality of the overall construction. One of my past machinists told me these were junk when he sent me some out of spec parts one time. So we got out his gauge blocks for some tests and he whistled a different tune.
For about $10 more (maybe not from this source) you can pick up a set that has a larger display. The display isn't the only difference. That model also seems more sturdy and more Mitutoyo-like in construction.
In any event, yeah, if you need a set, don't hesitate. But for most in this hobby, a cheap set of plastic ones will suffice (or a ruler

)
RandyT