Tungsten lamps are easy to test; if they don't light up, they're dead. You can even see the busted filament.
Fluorescent bulbs are another story. I've had bulbs that were flakey, and yet not entirely dead, which makes diagnosing a problem more difficult. I was tempted to buy a Kino bulb tester, until I looked at the price. Then I saw some others, on eBay, at about 1/5th the cost.
Do you have any knowledge of this? Is there something to the Kino tester that makes it worth a premium?