Extremely thick frontal turret and mantlet armor, making it nearly immune to enemy fire when hulldown - don't let them hit your cupola though, be sure to wiggle your turret when reloading to maximize the chances of getting a bounce
Good aim time.
Good gun depression that works well with the hull down philosophy.
105mm gun will provide excellent penetration with acceptable accuracy, rate of fire, and alpha damage.
Great view range.
Good frontal turret armor for its tier and even versus some higher tiers.
Side is sufficient for sidescraping.
Great ammo capacity with up to 63 for the 105mm.
Most of the modules carry over to the T32.
Weak spot on top of the turret is hard to hit when hull down unless flanked.
105mm gun does MASSIVE module damage
The sloping of the hull means you are able to reliably bounce shots with 160mm penetration from long distances (provided your lower hull or machine gun are not hit.
Hull armor won't stand up to guns with high penetration (ex. Tiger's 88mm L/70 or even the Black Prince's 17Pounder) and even some lower tier guns.
Large silhouette from all angles.
Excruciating stock grind if coming from the Sherman Jumbo.
Expensive ammo for its top gun; matches will soon result in negative income if you bounce/miss a lot as missing will cost you 1000 credits.
Awkward crew transition from the M6; the T29 has a 2nd loader and one gunner, leaving you to train a brand new loader and extra gunner sitting around in your barracks (unless you keep the M6 of course).
Rather slow rate of fire for the damage done; many tanks like the Tiger's 88mm can hit you twice while you're reloading.
The T29, although capable of leading an assault, can be very hard to coax out of a defensive position if it keeps its hull hidden and only exposes its strong turret. If put into a tier 8 or higher battle, it will have considerable difficulty avoiding damage unless it is put in a hull-down position. The turret armor can bounce almost any shell and fight back with good results. Just try not to get flanked. The T29 is somewhat slow and will gain considerable agility once the engine has been upgraded, making it superior in mobility than its Russian and German heavy counterparts. Therefore, it is highly advised to research the 90mm gun first and then research mobility upgrades to reduce flanking possibility. If you did not research the 90mm gun on the M6, and you have no free exp to use, then this tank can be difficult to say the least.
However, the T29 starts to shine the moment you upgrade its suspension. When the suspension is upgraded, the T29 gets a boost to turning ability and mobility, making it much, much harder to flank. Once you upgrade the turret, it gains a significant rate of fire increase on the 105mm gun, and rangefinders that look like weakspots but are in fact not even penetrable, while at the same time getting a boost to HP and view range!