Does Three Network's All you can eat package really totally unlimited?

Like Personal Hotspot on iPhone 5 I just bought it and using it right now wondering if it has any catches?

Yes
The only restriction is NO tethering laptop tablet using the phone as a modem

AYCE ata is LIMITED to mobile phone. If you tether and they can check that is the catch, YOU WILL BE CAUGHT, data is presented differently depending on the device.

All you can eat is unlimited

Truly unlimited
I have 2 "Three Mobile" phones on All-you-can-eat for about 2 years now - downloading about 20 Gb/month combined - never had any complaints from Three

Absolutely best provider (if you get signal: D)

EDIT: don't listen to the other answer. Tethering is supported and is truly unlimited