R Mi-24  

I've got some time in them back in the 90s working for a PMC in a certain unnamed African nation. Power was decent unless it got real hot or real high. The engines are bullet proof and easy to work on but rarely made it to TBO. Sand would just eat the engines without the proper filters. 

Pilot visibility from the backseat sucked. The gunner sitting up front would need to act as your eyes on the ground if operating near ground equipment or during running take offs. 

Maneuverability was somewhat limited due to it's size. The thing maxes out at 12,000 kg but we tried to stay well under gross, especially in the heat. Either way the thing is big and isn't anywhere as nimble as something like a 500. Also you needed to be careful not to yank the cyclic back in flight otherwise you would risk striking the tailboom with the MR blades. 

The YakB gatling gun was notorious for jamming. Also, finding 12.7 mm ammo would sometimes be hard to come by. We didn't use the gun much. We pretty much relied on the external stores for taking care of business. Cockpit was "sporty" but armoured so you're relatively safe from small arms fire. 

She always brought me back home safe so I can't say anything bad about her. She's a wonderful machine and over engineered in some respects. You can't overtorque the transmission, the thing is just built solid. And it's the only helicopter I ever flew with titanium rotor blades. Must be a soviet thing because of all the titanium they have over there in Russia.