Firefly is a tier VI British medium tank with the highest standard and premium ammo penetration. 171mm on tier VI sounds great, right? On medium tank platform even better? Nope. It's British.
Brits were bad at flanking (royal noobs) so they added 17-pounder gun to Sherman tank. Who needs maneuver when you may simply penetrate German HTs from front?
17-pounder gun. Do not even bother playing with another gun. You are here for gud pen, gud alpha (for that caliber), mediocre gun handling and amazing 6 degrees of gun depression making you (or at least me) feel really bad on hills or a bit bigger bumps. Forget about hill poking. Take a good long range sniping spot and pray to SerB for dumb enemies standing still to let you devour their HP. In close combat Firefly feels pretty bad - 4 seconds reload for 150 damage doesn't allow to spam an enemy.
Standard AP and premium APCR are simply amazing. Double tap “2” and even tier VIII super heavies lose their will to push - under one condition: gun has to hit and penetrate. This is the main flaw of Firefly. Despite 0,38 base accuracy (0,36 real) it struggles to hit a barn from 50 meters. I have pathetic 65% accuracy despite shooting fully aimed and with limited amount of blind shots. On vbaddict it's on 42 position on tier VI. Like what the royal hell? It's supposed to be sniper, not a derp.
Sherman Firefly carries 77 shells which is really good thing (much better than Achilles). It allows to fore some blind shots or keep a big guy on detrack till real help arrives.
Traverse speed is ok, I can't say a bad word. Turns like Sherman should but why it reaches max 36km/h? The only slower Sherman is Jumbo but in return it gets armor. What kind of logic is that? Firefly is like a runner with a backpack full of stones - it wants to go faster but it can't. Most of typical medium tank spots are unavailable for Firefly so a player is forced to play in second line (or first if flank falls and an escape is a good idea).
Be serious, it's Sherman.
Firefly has the worst camo among all MT VI - 12 base stationary. For me it doesn't matter. Without a BFG I prefer double bush or 445m+ sniping. 370 view range is workable, especially with binos.
It's easy - avoid non-flat areas, stay hidden, do not rely on maneuver and focus on heavily armored tanks beacuse 17-pounder makes a difference.