I’m squarely in the angled camp for several reasons.
1. More relaxed glassing position. It’s hard enough to “pirate glass” with one eye, no need to crane your neck under itself with a straight spotter and make it worse.
2. Angled spotter = lower to ground. More stability, smaller tripod, lower profile on the hill.
3. An angled spotter works for many different statures. I’m 5’11”, my dad is about the same. But my 3 other brothers are all much taller at 6’3”, 6’4”, and 6’5”. If we all used straight spotters we would have an issue with sharing glassing setups. “Hey bro come look at this bull I found in the spotter” is easier because I don’t have to stand on my toes to see through theirs and they don’t have to squat all weird to see through mine.
4. Glassing uphill is much simpler with an angled spotter. Just aim it up and look straight into it. Glassing downhill all you do is rotate the scope in its collar and look slightly sideways into the eyepiece as the objective points downhill.
The ONLY advantage I can see with a straight spotter is immediate target acquisition when switching from binos to spotter on the same tripod. That said, with practice, I have zero issue finding game in my angled, it just took practice.
At the end of the day, it’s all pole vaulting over mouse turds. Just pick what’s more comfortable and go find game!
I’ve read that, but I’ve never read it anywhere that I would deem a “credible source.” If there are any differences, I bet they’re so small they’d only be measurable by a machine, maybe not even then.