I’ve worked for two outsourcing companies and, from my personal experience, I have to disagree with TSIS. Sorry matey.
The first (CSC), I was TUPE’d across to. I tried for almost three years to make it work but it just didn’t. I tried really hard to get off the account of my pre-tupe employer and onto other clients, but ‘they’ wouldn’t release me – I was deemed “account critical” ( 🙄 ). As for the terms of the TUPE, it’s not worth the paper it was written on. After the first 12 months we were issued with new contracts and told to sign or leave – many changes to T&C’s. It was probably the most stressful period of my (20 year) working life to date. I ended up a mess and on anti-depressants.
I left CSC to go and work for EDS (I know, I know) and they were a bit better but bureaucratic beyond belief. To the extent that nothing ever seemed to get finished – projects just seemed to fizzle out.
I’ve since left them and gone contracting – happier, but still have the scars created by working for CSC
One piece of advice is to try and get away from the account (within the outsourcing co.) after you’ve transferred. My former colleagues who managed to do it are still with CSC and doing okay. Good luck.