[Typo3] Need references

[Uld]

Hello people,
I am currently working in a "Web-agency" and I recently made the
choice of using typo3 for one of my customers.
That is why I am currently searching web pages which could attest
quality of typo3 as CMS.
I am particularly seeking figures:  who use typo3 and on which scale?
Do big firms use typo3?
I am also searching details about reliability:  figures about major
bugs or potential hacking possibility discovered in typo3, speed of
bugs correction...
If you know Web pages which could help me in those research, do not hesitate.
Thank you by advance, Uld