I'm also in the process of changing over to Tigi colour having used Clynol since I trained 28 years ago! Yes it is very scary as I know Clynol inside out but they are so limited and don't move with the times. I'm moving very very slowly with it and the support i get from Tigi is fantastic, both my rep and the colour trainer are always there for advice. My decision to change was finally made when a customer asked for a paraben free colour, which Tigi are.
Basically I agree with Scottdolly, their colours are lighter....except the lighter colours from 9.0 upwards which seem to be darker! I'm sticking with Clynol for high lift as they perform much better than Tigi in my experience so far.
Tigi bleaches are AMAZING as Bluerinse says, i'm also a huge fan of Radiant Gloss 0/27 for toning, especially on colour corrections, it tones loads of warmth out
The range of colours is literally limitless....the colour world is your oyster!
On the negative side i have found the colour does fade a little, particularly on grey coverage....i must ask the colourist about that one, it could be something i'm doing!
x x