I would recommend some non-digital calipers, cheap digital are a waste of time. I have Mitutoyo digital at work and they are great but use analogue at home.
Why are they bad? I've had a pair of these for years and they've been faultless, for the few bike related jobs I use them for. Are they that inaccurate?
Because of the battery issues, I gave up on cheap digital at home and only use analogue (it is always ready to go!). Like I said, the more expensive digital verniers don't seem to suffer from the same problem.
I would recommend some non-digital calipers, cheap digital are a waste of time. I have Mitutoyo digital at work and they are great but use analogue at home.