ease of use is pretty important - i think. since this is your first HRM, i would get something less complicated. my polar S150 is okay for displaying and recording heart rate information. however, i find the interface a little hard to use because the buttons are small and the display is small. so, i don't use many of the features it has. they were lost on me.
i would get a simple speedmeter for your bike - to check speed\distance. then get a simple HRM.