My two cents (after 4+ years of using priming sugar) is that if you mix the sugar in a little bit of water, boil for 5 to 10 minutes and then pour the boiled sugar solution into the bottom of the bottling bucket before transferring your beer on top, you should be fine with just using priming sugar, and you will find the priming solution well mixed. It is cheaper, and the process has less chance of getting some sort of infection into your beer than using carb tabs.
Having said that, I have used the Munton’s carb tabs a couple of times. I used them when I was experimenting on carbonation levels in beers and I wanted to have multiple carbonation levels from a single batch. I like being able to put one, two, three, or four tabs into a bottle and vary the carbonation level.
Bottom line is, when I used them, I could not tell the difference in quality between “normal” priming and using the drops.
As far as sanitation goes, I just opened up some beers that were made three years ago using the tabs, and aside from a distinct sherry note that comes with age, I did not notice anything to make me think that sanitation was an issue.
So I would say, use the drops without fear, remember to keep your hands sanitized, however, (I wear rubber gloves and keep wet with sanitizer when using them) so you do not accidentally contaminate your beer. Also, pay attention when adding the tabs. It is easy to get “in the zone” and forget how many and which bottles you have put the tabs into!
Good luck and enjoy!