Also be aware that, in my opinion, all of these tanks are "tinker toys" in that you will end up having to tinker with them a lot.
All 3 of my tanks that came with smokers quit smoking. The stock smokers are notoriously fickle and fragile.
2 of my tanks ended up with flaky airsoft guns. Seller replaced one of them. The other died too late.
My Sherman had a motor with a dead spot in it; seller replaced it.
Both my Jagdpanthers, metal and plastic, have a problem with the treads jumping the idler wheel. Heng Long tanks generally have no track tension adjustment so you have to do this by adding/removing links, which I have not bothered fiddling with - I just manually pull the tread teeth back into the groove in the wheel again when it jumps out.
Higher end tanks may not have these problems, I don't know. All I have are the "cheap" Heng Longs.
Honestly my best tank is my first one - a simple Heng Long Panzer III with no smoke and no sound. It's got first-generation electronics so it only has one speed, go fast and stop.
But it's airsoft gun has never had a glitch and it will raise a welt if you shoot yourself with it.
The problem with the P3 is it's road wheels are two-piece and it routinely sheds the outer hub. Tank keeps going find but you have to go hunt for your "hubcaps" in the grass. I just super-glued them on.
Steve