The Lowe is a strong tank but OP? No, but I say that because I know its limitations and its weaknesses and the other players I face seem to know it as well. Basically you treat the Lowe as any other big tank in the game. You gang up on it, call in arty, or hit it from its flanks. The tank tracks as easily as any other tank so stopping it from moving is not that hard. Its slow turret movement makes it vulnerable against a fast tank or dealing with two or more enemies at once. Just use smart tactics against the Lowe and its not too hard to deal with. Personally I find it better as a sit back and snipe tank than one going out on the front as a spearhead type. Being the spearhead in a drive gets you killed a lot by an awaiting enemy I have found. It just doesnt move fast enough to get out of the way and get to cover when needed. Oh, and a T44 or an T54 can tear up a Lowe easily enough single handedly. IS3 and IS4 seems to do fine against it too. Havent met a IS7 yet but I figure its gun can tear huge chunks out of it.
I get the impression that it is as strong as any of the other 3 Heavy Tanks but is available without the hard work.
Apart from the Hotchkiss which should have been remedied now, each of the gold tanks are weaker than their counterparts. In my opinion, the Lowe outguns most of its equals and has superior shell bouncing armour but falls down in mobility.
The Gold M6 with sloped 191mm? armour is easily penentrated frontally with large weakspots in it's armour. I've not seen this in the Lowe, though front and centre is a bad place for a medium to be.
On the US Vs. German Vs. USSR Tier 8 Heavies... I've only played the T32 but faced everything enough times to have formed an opinion.
T32: Fearsome turret armour, weak hull (though not as bad as the T29, T34 or T30), gun feels weak for its tier.
IS-3: Probably the weakest of the 3. Armour can be frontally penetrated by a PzIV with 7.5cm L/70. Damn fine gun though.
King Tiger: Fearsome. A bit weak on the sides but frontally strong to anything below 180mm penetration and difficult to beat even at 200mm penetration. Reports of the gun being a big fragile, despite it being an extremely good gun.
At tier 9, the T34 takes a backseat. Armourwise it's a T29 without the ears and gunwise, it's not impressive.
The IS-4 is well armoured all around and is difficult to beat even with 220mm penetration at times. My Pershing still bounces on the sides and rear if I make a not so good shot.
The VK4502 with upgraded turret is nigh impenetrable by the IS-4's 130mm gun. It's turret placement, sides and its spontaneously set on fire skills are its weaknessed but frontally, it is an absolute beast.
Tier 10... not seen the Maus much, never had a chance to fire at one but with the fixes to its weakspots, it seems to be extremely vicious.
IS-7 is a faster, less well armoured (and bounces less) IS-4.
The T30 is simply a T29 without the ears and with a very, very big gun.