More than British, it were the Muslim invaders like Babar who plundered our country, temples, raped women, forced conversions and committed other atrocities. Before British, Hindus were slaves of Muslims in their own country. Comparatively British took much less, killed very few and were much more civilised and humane.
Some of the British actively helped Congress in freedom struggle and played instrumental role in activating humane laws, by and large left us to practice our own religion, setup industries, spread modern education, no discrimination in Government jobs and so on.
Can you tell the same about our Muslim rulers? British ruled us for 200-300 years but Muslims brutally opressed us for close to 600 years.
I would say that British essentially did unite India, gave us good infrastructure, modern education system and most importantly, freed us from Muslim rulers.
It was not best of the periods for India, but not the worse either. Better their graves than Muslim soldiers who were much more cruel.
