I would be careful to shoot down UFO's, because in Hardmode most of them shoot back.
I usually tend to stick with landed UFO's to have more loot, but if i need more money, i shoot down some ships of the alien in a region to attract retaliation missions on purpose to get some more money and some more exp for the soldiers.
As Hobbes already said it is balanced out, shooting down delays next wave, assault landed one, get more loot.
Also SIMON, you really need to get Laser Weapons in your playthrough ASAP since your next month is probably my totally loved Muton Month. Also you need to get global radar coverage. Once you interrogate engineers and navigators alien missions will increase, so you better get some more soldiers and skyrangers also. And sell the alien loot, do not sell Blaster Bombs or Blaster Launchers, because they are only available through collecting from aliens.