The rationale why this place is no less then a heaven is because:
1. It is a place which has the most stupendous weather at all times of the year.
2. It is a place which is nothing less than a heaven for photographers or cycling enthusiasts( because it provides the cyclists with almost a gain of around 500 meters in about 6-7 kilometers of ride plus there are around forty curves while you go up), haven't you started liking it, Yes I know that feel Bro :-)
3. The place is fully developed to be crowned as the best place to spend a weekend because it has several shops, a restaurant, parks for children etc to keep anyone engaged.
4. Paragliding, Yes you read it correct, it is one of the few places which has an option of paragliding activity.
5. Several temples, the most famous one of Nandi Bull, after whom the name of the place is christened.
6. And many more things for you to discover.
One thing which I should mention particularly about the place that it is famous for its Sunrise, people gather en masse at this place to witness the exemplary sight of the sun rising bearing the light which enlightens the whole world. People choose their own timings to visit the place, in whatever way they like but the gates of the place open only after 6 a.m, an important fact to keep in mind if you visit the place.
The Nandi Hills is well connected and very suitable place which can be reached easily unlike the Skandhgiri Hills, where one has to do the tiresome trekking to reach the top.
Also, if someone is into spirituality and practices meditation or yoga, this is a place where one should visit to get an environment full of peace and serenity, where the task of finding the Inner self becomes effortless.
In the end, I would like to mention that I visited this place on my Royal Enfield and the only cost I had to bear was that of Gas and some food, the costs will definetly increase if you plan your trip in any other way.
Conclusion in two words i.e. MUST VISIT.