If you're comparing apples to apples such as the good digital SLR compared to a good SLR 35mm film camera the digital will always be better and I venture to say that's across the board. It's lot easier to go to print with digital than go to digital from negatives, the higher megapixels will also provide a better image for really large prints i.e one meausured in feet.. Having said that you can get really good scans with the right equipment.
If you're interested you need a scanner that has option for the negatives for the best results. This will give you superior reproduction as opposed to scanning the printed image because the negative(or slide) is illuminated with a backlight. You'll also need a scanner that can scan a very high DPI since negatives and slides are so small physically. If it's a large project this is a lot of work no matter how you do it, IMO it's best to do it once and do it right.
The biggest issue when scanning is dust, this is especially true for slides and negatives because that little particle of dust becomes enormous. To prevent this you can purchase a scanner with Digital Ice, this is "flaw" removal system but works differently than software methods. Digital Ice detects physical imperfections (such as dust specs or scratches) before the creation of the scan and isolates them for removal. These types of scanners have come down quite a bit in price but are not cheap comparing to a standard scanner. You will also want to get some canned air to blow as much dust from the slides as you can before scanning. There are a few other scanners on the market with similar systems named differently but digital ice is the original, it can only be purchased with a scanner because it's hardware based, it's not software.
Other things to consider is to look into self feeding models.
Having said that you can get some good results from a standard scanner. It's just going to add a lot of work, manually inserting hundreds of slides or negatives and manual dust(noise) removal with software is very long and laborious task.