I've had a Vivoactive 4 for about a year and I'm ready to go back to my old Forerunner 220.
Using Auto-Lap, whenever the lap changes, the pace displayed goes wonky. For ex: if I'm running a 10:00 pace (and I know I am) when I go from lap X to lap Y, the pace shown will change to something really off like 12:15. It takes about .25 to .3 miles for the watch to get back to my actual pace and it happens throughout the duration of the run (short run or long). It's really annoying when you're racing and trying to make sure you're not going too fast or slow. This didn't happen on my Forerunner 220.
The pace displayed on the Vivoactive 4 is rounded. I did a race today where my pace would only display 10:05, 10:10, 10:15. Then the lap display would say 10:12. I don't understand why this newer supposedly more advanced watch has worse technology than the old watch I bought in 2013.
Overall I think the GPS on the VA 4 sucks. It's not consistent throughout runs. I did a 6 mile run a few weeks ago wearing both my VA 4 and FR 220. While the end result of time and distance between the VA 4 and FR 220 were pretty comparable, the pace displayed on the VA 4 throughout the run wasn't. Once I warmed up and dialed into my run, the pace displayed on my FR 220 stayed pretty much consistent (10:30), but the VA 4 would have mile 2 at a 10:40, then mile 3 at an 11, then mile 4 at a 10:15 (but going by feel, I wasn't speeding up or slowing down).
