My preference has been 165 mm cranks for a long long time. I've tried longer, sometimes giving 4 months to wow me. But still I go back to 165 mm.
I'm giving my old Paramount to my younger son in Colorado. Thinking that he'll be doing longer climbs than I have here and the fact he is four inches taller and also has legs longer than mine, I decided to put the 170 mm crank with 50/34 rings on the bike. I rode it yesterday on a 42 mile route that has some of the longest and steepest climbing I can get to starting from my home. Right from the start my initial perception was that I was thrashing more and that my legs were more tired.
And this feeling persisted for the entire ride and I was more tired at the end of the ride. However looking at my metrics for the ride, I didn't suffer any performance hits. I was actually two minutes faster on this than the previous same ride on my Tarmac. But there are other things in play that probably don't quite make this a fair comparison of short vs long cranks. Mostly the fact I'm comparing two different bikes now since I have no current rides with the Paramount to compare to.
All I can say is if you can, try them for at least a few dozen rides. If they don't work for you, then at least you now know. My inseam is 34.5" and I like pedaling at least 80 RPM. If you are a 60 - 70 RPM rider and like to stand while climbing, then I might suppose you won't like shorter cranks. But for now that is just supposition.