If possible, I recommend you take a trip to both cities and see what you like more. Spend a week in each, and maybe try to go to Toronto in the winter to see if you like it. Berlin has mild winters and doesn't get much snow, but Toronto can have harsh winters. Summers in Toronto can be hot and humid, which you might be used to already (since you said you're from India).

The biggest advantage to Toronto over Germany is the proximity to major US cities. Like it or not, most of the "tech innovation" is centred in the US.

Also don't count on the TN (which is not a visa, btw) sticking around forever. If your main reason for going to Canada is border mobility, you're probably better off staying in Europe. An EU citizen can live and work anywhere in the EU. Canada and the US have a close relationship, but NAFTA (which is where the TN comes from) could be gutted whenever the politicians decide that's what will get them reelected.

All things considered, if I were in your position (knowing what I know) I'd go to Berlin. It's more trendy, has better public transit, milder weather, and Europe has much more culture to explore and learn about than Canada (sorry).