Avoid
Short version (recap):
Avoid, because - NEST are too busy to help you. They assign you to one worker who is in charge of your tenancy and only that worker will be on your case and willing to help you.
Long version:
Terrible, and disappointing service.
I was a tenant on a property lease. And when I wanted to move out and pass my tenancy on to another person this took hideously long time! My real estate agent had JUST told me that I should expect up to two weeks for the whole process to be handled from when they received the new tenants application. I made sure to help her fill out the application form perfectly and had myself and my existing flatmate inform consent to the change of tenant.
Now it took FOREVER for the real estate agent to get to our case and as I didn't hear from her for weeks I emailed her several times only with the answer that she was too busy. I then started going down to the office daily to try and catch her as well as to receive answers to rising questions on the matter and the receptionist told me she could do nothing but ask me keep contacting the agent. I ended up moving out of the country before the tenancy swap got issued! Consequently I had to pay approximately 10 days extra rent and the girl who waited to move in had to stay at a hostel for that same time. But worse than that I lost complete trust in their service and the last three weeks of my semester abroad be affected by worry of wether my case would never be handled leaving me stuck with a tenancy that I couldn't quit. Looking back I understand that NEST is reliable but this process was just too slow and it felt SO uncomfortable not to get help and answers when I needed them.