As an ex baxi engineer (senior engineer for 17 years) I personally would fit a baxi 800 as it has a 10 year warranty and filter in the box. The problem with Worcester is the really want their accredited installers fitting them and so the get the benefits of even longer warranties. Even as a Worcester engineer I'm not able to get them.
@Insert Coin yes the netatec was easily the worst boiler ever made by baxi, or by any other manufacturer. Unfortunaly they relied on one company for supplying the gas valve and the reliability was terrible. My mum had a field trial one which broke down 8 times in 18 months and was ripped out and replaced one Christmas eve evening.
So for me. When fitting boilers, if the long warranty is important then its the baxi 800, if its not then the Worcester cdi compact is also a great boiler with 8 years out of the box. I would also say, Worcester reliability is way better than baxi, ideal, glowworm and valiant, but not servicing will have an impact on this.