The Konisch is meant to be used with only gold rounds. The regular rounds only do 85 damage compared to the 165 of the gold. Not to mention the gold rounds have 225 pen, which is alot better than the 88, and is capable of penning any tier 8 frontally. The 225 pen also allows you to pen the turret of most tier 4-7 tanks (t29 the obvious exception). Also abuse your higher rate of fire to the fullest, you can take 3/4 shots for every one of a KV-1S, so if you see him fire, dont peek out shoot once and hide, put at least 2 or 3 shots in him before you take cover.
The gun is also accurate and the tank has a decent camo rating, so its capable of sniping safely in higher tier matches. The gun also shines with deadeye when it comes to causing fires, with a high rate of fire (pun not intentded) you can cause alot more damage by aiming at enemy tanks engines/gas tanks.
The only downside to this gun is that most games you'll lose around 20k credits (more if you dont have prem). However if you stock up on those half off sales (I got 3500 rounds on the last one), you can still crack a profit. I however dont really care, as his is one of those tanks I keep around for fun.
The tanks isn't exactly a medium, it should essentially be considered a faster heavy tank. It does benefit from the better engines, but the tank won't "zip" around the battle field. It does have excellent armor for it tier, and with proper angling its capable of bouncing alot of shots.