I’m a competitive marathoner and moved up to this from an older model, 201 I think. Anyway, I use the product for long runs, tempo runs, and especially, interval training. My eyesight is fine, but the 305′s worst feature is the extremely small font makes it difficult read, especially when watching rest times, etc. for intervals. Weird, it tracks the pace ok when I’m running but often when I’m standing still it still shows a variable pace. Not overly impressed, will look for something besides a Garmin product next time although there aren’t a lot of choices.