Hi Rach,
The primary difference in preferences comes down to a trade-off between speed and quality. Clippers get the job done much more quickly and efficiently but leave less room for custom lengths in different coat areas. Hand-stripping is when you remove the loose guard hairs using your hands, often pulling the dead hair out by the roots. Groomers tend to prefer clipping due to its speed, but if you have the time and patience, your dog's coat will be healthier and mat less with hand stripping, but it may be less comfortable for your dog. Hand-stripping gets the best results with wiry, coarse-haired dogs like Terriers and Spaniels.