The Cromwell was the most important British built cruiser tank of WW2. It was second only in importance to the Churchill as the prime British tank in 21st Army Group. It was the first British tank, to combine reliability, high speed, an acceptable general purpose gun and reasonable armour. In 1943 it would have been a winner as on most counts it was superior to the Sherman (especially if you factor in the far lower silhouette), but it did not reach the troops in a usable version until just in time for D Day.
It had a low silhouette and was armed with the 6 Pdr gun, 95mm close support gun or the British 75mm QF, although only the latter two weapons seem to have seen combat. Armour protection varied, but eventually got up to 101mm on the front plate in the up-armoured versions. It was the main equipment of the British Armoured Division's Armoured Reconnaissance Regiments (in effect adding an extra medium tank battalion to these divisions) and wholly equipped 7th Armoured Division (the Desert Rats) in North-West Europe.