I have both the Cateye Astrale 8 and an Echowell F2 on my two road bikes. In all honesty I prefer the Echowell. It will record max and average cadence and you can see speed, cadence and something else (time, distance etc) on the screen at once (you only get two things at once on the Cateye). The Echowell has the added advantage that it is also substantially cheaper.
Max cadence the other day on my Echowell was 191rpm (done on the flat in 30/25 on a triple). I was pretty stoked that I could actually spin my legs that fast.