There are legion but many people state that Chieftain had great armour. Well the front perhaps but the sides were pretty dire with less than a late model Panther. As far as failures and engine power go, the transmission problems were solved pretty early on but the engine not until it was too late and an abiding memory of mine is Chieftain going uphill. Sounding like a dinosaur having its tackle ripped off. I know my opinion is an unknown quantity but I actually served on those bloody things. Some failures came about because we just did not do much with them at the time with restrictions on mileage, track mileage and eventually engine revolutions.
Some 115mm rounds could penetrate the frontal armour but only at very short range.
""Stillbrew" armor package was developed to give it immunity from T-62 (and not really T-72 as some sources say)." inaccurate, timeline.
"Chieftain would have fared quite well with Israeli crews, for sure". The Israeli crews were effective mainly through training tbh, a consistently proven fact.