I just moved over to iOS and decided to pick up an Apple Watch. I went with the Series 1 but I'm really debating whether I should return it to get the Series 2 since I don't carry my phone with me on runs. I don't really need to see a map of where I've ran and I don't swim, but I would like to have a fairly accurate account of the distance I've ran. Is the Series 1 accurate enough for this? Is there any other reason to snag the Series 2 instead? TIA!