The Bison is a Tier III German Self-Propelled Gun, branching off from the GPz MK IV (e).
The Bison is a powerful SPG, with a surprisingly fast shell velocity, accuracy, alpha damage, and splash radius in its tier. The calibre is also unusually large. In fact, it's the first SPG that can deal stun!
Accuracy is above average for its tier, especially the calibre: 15cm. However, this is negatively affected by its narrow gun arc. It blooms significantly when the tank turns, but it's compensated by a relatively fast aim time (For its calibre at least). It's also worth noting that its fire arc is very high. Combining with a fast shell velocity and gun stats, it can be deadly.
When defending itself, it can simply corner itself, making flanking harder. Gun accuracy, shell velocity, alpha damage, and splash will help in self-defending. Combining all of these can make TD mode possible.
However, it has disadvantages:
First, it has bread armor. No bounces will occur and you will always take damage from shots, especially when its open-topped.
Second, it's very sluggish, making relocating somewhat of a hassle, especially when trying to save your SPG from an open flank. Also, because of its weak engine and suspension, adding weight is not advisable.
Third of all, despite its gun it uses, it has a short gun range, which means it has to move often to move into gun range of targets. To put into perspective, it can only shoot 3/4ths across Himmelsdorf.
Fourth of all, its a low tier, which means players new to the SPG playstyle will struggle because of its high tier-like accuracy stats. However, experienced artillery players that play this tank will find it very fun to play, especially players who are used to narrow arcs and 20 second reloads (And higher).
Many players would rather go through the Bison branch than the Wespe branch, since the Bison and the next SPG has better guns stats with an acceptable reload rate.
Overall, it's a very fun tank once you know the SPG's pros and cons. It can even be considered as mini KV-2 #2 (Cruiser II is mini KV-2 #1).
The following is spoilers and historical inaccuracy about this vehicle! Do not open unless you are prepared for the spoilers! The reason Wargaming did this is due to game balancing in most cases!