It depends entirely on why you're visiting. For IT parks, stay near Whitefield, Electronic City, Bellandur or Sarjapur Road. For restaurants and nightlife, Indiranagar and Koramangala are central. For rail or bus connections, Majestic is closest. Bangalore traffic is heavy, so staying near your destination usually beats saving a little on the room.
Bangalore is comfortable most of the year thanks to its elevation. October to February is the most pleasant, with cool evenings. June to September brings monsoon rain, which can make traffic considerably worse.
Namma Metro covers many major corridors and is usually the fastest option during peak hours. App-based cabs and autos are widely available, but road travel between distant areas can take well over an hour in traffic.
Yes - it's one of India's most-visited cities for business travel. If your meetings are in one specific tech corridor, book a stay in that same area rather than in the city centre.