Dont quit on the panther, i dont know if you have the l100 gun, but if you do have, play as if you are a tank destroyer. Averagely I kill 3-4 tanks every round with panther, the gun is just really sick.
For me Jagdpanzer was ok, i used the l70 after the buff instead of the 88, i though the accuracy and penetration were more important than the damage, but jagdpanzer 4 isnt really special or unique.
I have jagdpanther now, a pretty solid TD, but due to the increase of the tank size, it is much harder to remain hidden in bushes as you are used to with the lesser tanks. Honestly not really interested in the later tier tank destroyers, but if i were to carry on, i would go with the jagdpanther 2, think the mobility is more important that the armor, especially in higher tier battles.
Easy Eight is simply the coolest tank i have now, with 100% crew, vert stabilizer, gun lay drive and a rammer, the thing is soo damn good on the move, very agile and accurate and can turn enemy tanks to scrap in seconds. I have unlocked the T20 and the M36 Jackson but i wont advance any further in the American tree, easy eight is the best.
I also have an IS and KV3 available but i just really dont like the heavy tanks anymore, i had fun with KV1 and derp gun back before patch, and when the KV3 was tier 6, but now it is moved up, Ive dropped it. Also felt a bit cheated because i wasted xp on the IS and then the KV4 came.
Pzkpfw 4, i didnt use it in its Schmallturm era, but i bought it after patch, pretty solid tank, but definetly weaker than the pz3/4, and also poor gun compared to the T-34 and M4 sherman counterpart, they should buff the L48 gun (actually overhaul all the german guns), with it i am going for tiger because it is a sexy and iconic tank, and maybe King Tiger, but then no further.
I also intend on keeping the Panther, Pz4, Easy Eight and the Tiger and Jagpanther and i am pretty statisfied. All the other is just cool extras.
Though the E50M and the future Leopard 1 really do look sexy