Jadgtiger any day.
It seems that you forget one main thing about CoH2. Paper-rock-scissors rule.
Infantry < ISU < Jadgtiger.
You have awesome AI unit and very good AT unit. OK, good for you but Jadgtiger completly denys your AI abilities. Because of range it's pushing back your ISU all the time.
The point is, even if you have ISU it wont do anything because it will be punished by Jadgtiger.
Of course, in games like ISU vs PzIV, Panthers, KT - ISU is better option.
But if we are talking about army with ISU vs army with Jadgtiger, I would go for second army. Your ISU will be useless if there will be JT on the field.
Even if it was Elefant vs ISU, I think I'd still pick ISU, because the Elefant has awful accuracy at long range.
I cant agree with you. Just today, I had 4v4 on Rostov. We were closed down due to huge crew weapons suads. Then 2x IS2, 2x ISU, 4x t34/85 vs 2 Panthers, Pak40 and 1 panzergren schrecks. We wanted to give up but we decided to wait for my Elephant.
And it was crucial moment. One Elephant with support was able to push back all their units. It ended with 30k dmg and from 99 - 450 VP we went to 99 - 0.
So if You asked me, Elephant is awesome and I almost always go for it.