I have hard time every year when it comes to this too. Have to balance between budget and coverage. So far MSIG has the best balance for my Latio. I have been with them since my Year-2 after AIG. The problem is that they are getting abit pricier already.
Here are some add-ons points for decision-making:
(1) The more options you want, you got to pay more.
(2) If you deem that you are overall a safe driver, don't bother about NCD protector until it's 50%.
(3) Cheaper insurances do not cover lotsa things like full settlement for total-loss, all-workshop, loss-of-use etc
Aviva is cheap upfront. But once you add some necessary options, it can be more than MSIG.
Another lower cost option: Tokio Marine.
Hope this helps.