I've used both Bushnell and Garmin hand-held devices (as opposed to actual watches). I've always thought the Garmin was the more accurate of the two brands. But then, I've only been able to compare them to the distances marked on our sprinkler heads & you can take your own view on how accurate the marked sprinklers may or may not be. I also thought the Garmin to be the more robust & dependable of the two. (Have had several, but that's only because I keep losing the damn things)
I used to have a Garmin S1 and replaced it with a Bushnell Ion.
As far as accuracy of distances goes, they seem on a par to me.
GPS isn't ultra precise anyway - take two identical watches next to each other and they will sometimes show readings a couple of yards different.
I replaced the S1 because its non-replaceable strap broke three times and was no longer repairable. Other Garmins have replaceable straps, but they are still a proprietary design, whereas the Bushnell strap can be replaced with a normal watch strap.
Never had a Bushnell but my Garmin Venu 2 has never given me cause to doubt its accuracy and has all the measuring and recording information I'm likely to need for golf.
It looks great and is an excellent smartwatch and fitness tracker. If you like tinkering, there are some great customisable watch faces.
I've also failed to put any scratches on the lens or case while bodging various DIY jobs, surprisingly.
I rarely bother wearing my Christopher Ward watch anymore, which is the only downside.
If you're a member of any kind of employee discount scheme it's £210 straight from Garmin, which seems like pretty good value for money.