jsu bought some walkie talkies they were quite expensive and the battery life is just what i wanted.The only ? i have is will a range of upto 5 km be ok for borovets? they had other that were cheaper but the battery life was not as good.
As far as I am aware the distance of the signal depends upon the terrain/environment you are in. With having alot of mountains to block the signal, you may find that the range is reduced.
Our walkie talkies are fine on the lower slope OR on the top. Never found ones with a range from the top of gondola to bottom. Can sometimes speak from middle station to someone at bottom.