The only issue is the price. If you're willing to pay it, you'll get everything that you're expecting.
The location is perfect if you study at QMUL - practically on campus, 50m away from a Sainsbury's, and close to both the Mile End and Stepney Green tube stations.
The rooms are nice, even if they are a little small; you'll have your private bathroom and a kitchen with a microwave and an induction cooktop, although annoyingly no oven.
The study spaces in iQ are great. You can book a smaller private room to study alone or with a group, or just use the public study room, which is also very nice, with lots of plugs available.
The gym is very good, and probably my favourite part about iQ. It's small, but the equipment is modern and comfortable, and it's actually a proper gym with a cable machine, power rack, dumbbells going up to 30kg, a punching bag, etc. It has a working AC and two rooms which could be used for changing. Very convenient that, to work out, I just need to go downstairs.
I also liked all the other facilities at iQ, including a table tennis table and the cinema room, which was also very good.
The fire alarms were not an issue at all for me. Sure, they'd go off quite often, but usually only for a few seconds, and almost never during sleeping hours (there was only instance in which a fire alarm woke me up, and it was due to a technical issue).
Overall, I had a great experience at iQ. Again, the only issue is the very high prices. Otherwise, I'd definitely recommend it.