I recently got the KV-1S, and it did not disappoint, and I'm definitely keeping it for the future. However, I am now facing the choice between the KV-3 and the IS. Note that I am not rushing through the tank line, and have taken the time to get every Soviet non-premium tier VI tank (except SU-100, but I'm about to) to see what I like with the allegedly easiest-for-noobs nation.

I have nearly enough XP for one but not for both. I'll probably get the other right after, but which one will be the easiest to play and grind credits, winrate, XP, and also the most fun?

Also, since the tank I pick first will have more XP quicker to progress down the line, which line is better to progress down, IS-7 or IS-4?

Thank you for taking the time to read through this!