The Canon Powershot SD630 resembles closely to the Canon Powershot SD600. The main difference is that the SD630 has a 3" LCD and no optical viewfinder while the SD600 has a 2.5" LCD and an optical viewfinder. As a result of this, the SD630's controls are smaller and somewhat harder to use. Luckily, the LCD works under most lighting conditions. When the light is quite bright, it is possible to see where the subject is, although it can appears quite washed out.

Overall, the SD630 is a good digital camera. It is definitely better than the average ultra-compact. However, the SD600 would be preferable due to its optical viewfinder which helps in bright light and helps follow subjects during continuous shooting. Since its performance is nearly identical to the SD600, you can visit its review for further details. For a superior ultra-compact alternative, go for the Fuji Finepix F30 or Fuji Finepix F10. Both these cameras produces significantly better images in low-light, have more powerful flashes and much longer battery life.