The N5 might not look the sexiest bit of kit but it offers a solid performance, and good signposting puts it among the most user-friendly HRMs here. You can set three different HR zones and save data from 30 sessions in the memory, including valuable info like the amount of time you spent in, above and below your chosen zone along with your average and max HRs.
You're also given a calorie count and the percentage coming from fat, although the accuracy of both will vary between individuals – take them with a pinch of salt. You can show your HR as a proportion of your theoretical maximum too, although this is based on your age and you can't alter the figure if your true max is different.
The N5 comes with two stopwatches that you can run at once although, unfortunately, the one that features a lap timer isn't the one that works with your HR data, so lap details don't get stored. The closely-set buttons are fiddly to work with gloved hands but you do get a bike mount, and overall this is a very capable monitor.