Specializing in WWI aviation history but know a fair bit about WWII as well. Small arms history ranging from US Revolution, US Civil War, WWI and WWII. Tank warfare from WWI through WWII. Generally always been fascinated by the equipment and materials used as opposed to the actual battles themselves.
It's worth it. I had a lot of time spent in my Tier 8 which helped me quite a bit to the tier 9 and then the tier 10. To me it kind of felt like a downgrade moving my way up to the rTier 9 and then 10. But it's a trade off for that extra turret.