Pros
Great college community (partly due to the distance from town meaning that people socialise in college more)
Swimming pool and fantastic gardens
All the sports fields are on site
More relaxed atmosphere than in some colleges. Academic aspiration comes from you and there is less peer pressure to overwork yourself and a more positive and supportive attitude from directors of studies and tutors.
Very diverse and accepting community
Also very caring community - just one example is that you meet the Mistress (yes, we have a Mistress, not a Master!) a few times over the course of three years in small groups, whereas at some other colleges (especially those of Girton's size), I get the feeling its all a lot more impersonal.
AMAZING history - the only women's college that is now mixed. Our great hall has portraits of past Mistresses all round it - very different to most colleges that have at most one or two portraits of women. The Old Girtonians were incredible people and its a privilege to be a part of their history. The fact that it is further out of town is a reminder of the way they fought for women's rights to education and equality (they weren't allowed to be near the men or part of the university at the beginning).
The very equal balloting system which means you are basically guaranteed a great room for at least one year, without having to pay loads extra. It is also not based on academic or extracurricular achievement (unlike some other colleges), since at Girton all types of people and skills are valued.
The great self-catering facilities! Some colleges will say they have 'self-catering' facilities and it's actually only a microwave or maybe at the most a plug-in hob. At Girton, you have at least a decent-sized kitchen (and some of them are huge!) for each corridor (usually per 8-10 people), with an oven, four hobs, fridge, etc. As the majority of people eat in hall most of the time, there isn't much competition to use the kitchen, so if you want to cook a lot it's totally fine - but for everyone, it is really nice to have the option.
Girton is one of the only places in the country that is home to a black squirrel population.
Really fantastic sports facilities which everyone, not just the rugby team, uses. (Swimming, gymming, tennis, squash... you name it!)
Cons
Occasionally the distance from town can be annoying
The Girton distance jokes from other colleges