R6 cup, one-make events - all can be great fun where you can see the whole circuit (or nearly) like Mallory Park or Brands Hatch short-circuit. Some of the most entertaining racing I ever saw was the "Despatch Riders' Destruction Derby" - the LC350 races, with a certain Hill, D taking part!
My point is that at the TT no-one sees a race - you see motorcycles being ridden skillfully and fast on whichever challenging section you watch at. I used to love watching from around the Bungalow, where you can glimpse a rider approaching round the Veranda, then burst into view, cross the tramlines and disappear up what is now Hailwood Rise (?). It was the same at the Gooseneck - Manx Radio told you who was at the Hairpin, then you saw a rider - or sometimes two or three, sweep up towards you, round the turn and off up the Mountain, often getting signals at the same point.
When it could have been a 350 yamaha, or a 4-cylinder Benelli, or a 3-cylinder Mv or a......you could compare how they handled, braked, and revel in the wonderful sounds. Nowadays it is more like a higher-class Mad Sunday, with less traffic!