I both a trail tech and a wathdog. For general trail use and introduction to enduros they are a good choice. Once you become more procifient at enduros you'll want to buy a computer. The trail tech is much better now that you can adjust the trip mileage. Just be careful not to wash the bike with it on, mine nearly died from that routine.
I got tired of fixing my 2001 KTM's mechanical odometer so I purchased the Trail Tech. It works fine with the Watchdog since I can use just one magnet. It is almost worthless for Enduros except for use as a odometer.
Even as an Odo, it has severe restrictions. You can't reset it easily, but the mileage can be set. It just requires a lot of time to set to another mileage and I am usually in a hurry.