My needs are fairly simple....I have tried (and liked) several of the Polar and Timex monitors that require chest straps. But this device is slick....especially becuase it links with an iphone app--and I was using the iphone for music on my workouts and/or for gps on outdoor walking, etc.
However, the Scosche Mytrek app is horrible....inconsistent, doesn't work, requires my iphone to be rebooted, etc. But there is an app, Digifit, that recogizes the device and works great. I use it every day. Haven't fully compared every feature of the two apps, but it's kind of a moot point as my needs are pretty basic, and the Digifit works great, and works and plays well with other apps (especially when multitasking). Without the Digitfit app, I probably would rate the device a 1 rather than a 4.
Only downsides are that the device needs to be chaged between uses, and overall the iphone battery life is an issue when using this (and iphone criticism, not a Scosche criticism!) If you're using the app, GPS, listening to music, occassionally surfing the net while working out, etc. it really runs the battery down quickly,