Up until 2 years ago I had no issues with Admiral, in fact it was the longest I had held my motor insurance with the same company. Something seems to have changed then though and they started the renewal quote nonsense of dramatically increasing their premiums for no reason but suddenly dropping it back down when you say you will switch.
I am now giving Direct Line a go, no problems at my first renewal. Admiral will be pretty low on the list if I ever have the need to change again.