The Challenger 2s are niche but usable. But the overall line up isnt the strongest currently. 10.3 is definetly the last time Britain is decently well rounded. Not that top tier is bad though. but we could really do with a dedicated SPAA system and a really good IFV at 10/11.
But the Challenger 2s have issues a mile long, but starting with the next major update. They might be getting fixed. So it really comes down to how much you want the Challenger 2s.
That being said, Sticking with a 11.3 line-up and avoiding the 11.7s does seem to net quite a few downtiers recently. Whilst the BN, 2E and 3TD have notable advantages, The 2, 2F and TES arent to be scoffed at either, if played to their strengths.
I do highly recommend downloading an alternative sight for the tanks via WarThunderLive. It makes such a difference, as you need very accurate shot placement
A core strength of our top tier line up though is our CAS. The Tornado Gr1 is a bit of a powerhouse of a CAS with the PGMs, so long as you dont encounter any Pantsirs and the Apache is very good too.
Im sure its been said already, but honestly wait till the new major and see how they rework Challenger 2s as that will decide whether they become relevent (for the first time since their introduction into the game) or stay dead.
I think the main change coming is a new mantlet. The hope is this will give us much better protection in this main weak area
but I do also think there is also several outstanding bug reports regarding the ammo (it shouldnt be so easy to detonate), the armour around the ammo and even the ammo placement.
fun fact just shoot the tracks of any russian tank with HE (facing front) its an insta kill with the 120mm gun :) can also try it out in test drive works on t90 aswell