After seeing a local racer using one of these I decided to pick one up.
After trying it at Bury I was really impressed with how well it works. The transponder is pretty easy to install and the sensor / app just worked, didn't miss a lap.
It can be difficult to feel when your quicker/slower when practising without timing gear.
Even with timing you don't normally get instant feedback, having your lap time spoken to you as you pass the sensor was brilliant.
Feedback from Ian Joyner on Oople
I was really impressed with how well it work....