Some suggest that third party commenting systems, such as Disqus, provide a superior service. It's possible that, to some, third party commenting systems are more feature rich - but only Blogger native commenting provides one essential feature, in comment moderation.
Blogger commenting is one component, in the global Blogger / Google spam classification and mitigation strategy.
Blogger blog classification, Blogger commenting moderation, and various Google services, all contribute globally to spam detection, and to spam removal, in Google Internet space. Each service both provides input into - and accepts input from - other services.
Third party commenting products, while they may have some interesting design features that Blogger won't include, won't necessarily contribute to the Blogger blog spam classification effort, or to the community commenting moderation process. Nor will they accept input from Blogger blog spam classification, or from the community comment moderation process.
If you, as a blog owner, believe that Disqus - or other non Blogger commenting products - provides more useful service to your blog, you're entitled to use any service, that you can make work, in your blog. It is, after all, your blog - and this is one feature in our blogs which Blogger / Google leave to our discretion.
As with all third party accessories and services, however, you will get limited support, for any problems. If you break your blog, you'll have only yourself (or the provider of the third party service) to support your problems. You may even see the blog deleted or locked, because of suspected malware.
When you use a third party commenting system, there are two details to consider.
- Integration of existing comments.
- Post template modification.
When you install a third party commenting service, you'll have the service import existing comments into their database. And, you will have to install the necessary code into the post template - and deal with ongoing changes to the post template, in the future.
If, in the future, you want to return to use of Blogger commenting, you'll have both of the above details to consider, in reverse. Third party services, while they may provide importation of Blogger comments into their database, may not provide a reverse service. Nor are they likely to provide easy reversal of post template changes - particularly as the Blogger post template may have been changed after installation of the third party service.
If your blog uses an alternate product like Disqus, right now, you'll probably find it easiest to refresh the post template, to return to Blogger comments. If you have various custom tweaks in the post layout, you may not find this to be a pleasant solution.
If you are contemplating changing your blog, to use Disqus - or another alternate commenting system - you may do well to consider all of these issues, before changing.