[stevehertz]

1) How noisy are reel to reels?

The answer is, how long is a piece of string. They all differ and even then a specific model of deck will vary wildly depending on its state of maintenance, age etc.

2) How can anyone record from a microphone with that racket going on?

In recording studios the recording machines are in a separate control room to where the recording is taking place. So, to obtain the best, quietist, highest signal to noise ratio, place the recording machine in a different room to the mics. That's regardless of the quality of the machine and its state of maintenance.

Finally, the deck you have there is not a particularly quiet one. The manufacturer's signal to noise ratio (never mind any mechanical noise) is quoted as a very average 52dB.