The differences between gorilla safaris are detailed below:-
First of all the price for a Rwanda gorilla trekking permit is US$1500 yet the one of Uganda is US$800 per person.

Ease of Access: Gorilla trekking in Rwanda provides an easier option and easy to access from the airport. The town of Ruhengeri, off for trekking in Volcanoes Park Rwanda, is only a few hours’ drive on excellent roads from the capital – Kigali. Tracking mountain gorillas in Uganda a very long which is approximately 8-10 hour drive from the international airport in Entebbe. The shortest gorilla tour in Uganda is a 3 days gorilla safari, due to the long distance as compared to Rwanda where you could see gorillas in Rwanda in just a few days.

Harder Trekking : Tracking mountain gorillas can involve 2-4 hours of hiking to find them. In both Uganda and Rwanda this is going to be a long day and the hikes can vary quite a bit depending on where the gorillas spent the night and which troop you are seeing. That being said, the general experience is that gorilla treks in Rwanda are slightly easier while those in Uganda are slightly more strenuous. Again there are no guarantees either way. I have friends who hiked for three hours in Rwanda before finding a troop while my group came across a troop in just over an hour in Uganda. For more information about what to expect (and what to bring) on the day of the trek

Don’t underestimate the tiring effects of being at high altitude. Trekking takes place 8000-10,000 feet above sea level, not high enough for altitude sickness but high enough to knock the breath out of anybody, no matter how fit, who has just flown in from a low altitude. For this reason, visitors who are spending a while in Rwanda might think seriously about leaving their gorilla tracking until they have been in the country a week or so, and are better acclimatized (most of Rwanda lies at about 5000 feet).

Better Gorillas: There is no difference. There are 12 habituated troops in Rwanda and 25 in Uganda and they can move freely between the countries so this really doesn’t need to be a consideration. The gorilla trekking system is similar in all countries and because gorillas are followed on a daily basis, a sighting in all the locations is virtually guaranteed.