Mr Long comes highly recommended
When i do cars myself either Meguiars or Menzerna (intensive and final finish) products using a Porter Cable Rotary buffer then to finish off Victoria Concours Wax..
Auto Glym products are also very good.. on black the resin polish is good..BUT when the bodywork is warm to touch its a pig to remove.. SO on Black cars use AG's Ultra Deep Shine... ive found hot or cold it goes on perfect and buffs of nicely!
If you want to be even shinier using AG's stuff get the Extra Gloss Protection, apply it an leave it on the paintwork for about an hour then buff to remove