I have had mixed luck with Ebay Dial indicators. The Best Test Indicators still in boxes have all been good buys for me. But, almost every loose regular dial indicator has been marginal at best. I did repair one and its okay.
But, almost every used precision measuring instrument which is still in the box usually is a safer buy IMO
But, that said... NEW Chinese indicators from Shars have all been very nice IN MY OPINION. I have to admit, they are smooth and work well. Its hard to go wrong with them at the price of @ 30.00 . They are very nice indicators in my opinion .