I have the IMT-500. It's a very nice small little tuner and seems to be accurate. My other tuners are non-clip on chromatic tuners: the Korg DT-3, and Korg CA-30. All three of them show the uke to be in tune.
The IMT-500 appears to have been replaced by the IMT-900 (which adds a transpose feature from C to Bb for brass, etc.), so the price on the IMT-500 has been dropping. The 500 is a great little tuner.
The IMT-500 is a hair slower in responsiveness to my Korg tuners, but this is really picking at nits. It's about the only nit I can find. The IMT-500 is still plenty fast.
The calibration goes from 430-449, so you will be able to tune to play in most any concert pitch someone would want to use.
The IMT-500 also has a "Flat" button. This is helpful when you have a capo on the instrument and need to tune. Each time you press the flat button it drops the note a semitone. This will allow you to compensate for the capo and tune normally.
The clip is plastic with rubber feet on the top and bottom. The clip is a hair wider than 3/4" - nice width. The head swivels and tilts. You can twist it to be seen at any angle. The spring on the clip has good pressure and the tuner stays in place.
The face is an LCD panel and it lights up green. When you pluck a string the note shows up on the screen and a black lcd needle swings to the appropriate place on the scale to where the string is tuned. Straight up is in tune and this is marked with a small arrow. It is easy to see when the string is in tune.
I am using this with a soprano Flea. Flea's and Flukes have odd shaped head stocks. I find this tuner works very.