The version in the Ubuntu repositories will only receive bug fixes during a release cycle, not new features. This version has been tested with your version of Firefox, and is fairly stable.
If you use the unpackaged version via Mozilla Addons or elsewhere, it'll receive all new updates by the maintainer of the addon. These may cause breakage, depending on the level of testing upstream puts their code through. In Adblock's case, I suspect the level of QA is high, so this is not a very pressing concern, but one to take into account nevertheless.
Firefox will refuse to install a newer version of the addon if said version no longer supports your browser version, so you don't have to worry about that.
The main difference is that the Ubuntu-packaged version is feature-stable (its behavior does not change) as well as reliability-stable (it will work consistently) throughout the release, whereas you don't get those guarantees from using AdBlock's extention installed externally.
If you're installing it for more than one user, by all means, use the packaged version. But if it's just for you, I think the locally installed version is fine.
The only difference is that the version in the Ubuntu repositories will usually take a day or two longer to be updated.
If you install using the Add-On manager (as opposed to going to the website) it's my understanding that it installs from the Ubuntu repositories anyways due to the ubufox plugin.
I have more 60 extensions installed and I always get them From Mozilla. Some updates might cause problems but they are usually fixed right away, specially AdBlock and NoScript.
I would recommend using firefox's addons menu, as it is updated IMMEDIATELY when the developer of the addon pushes out a new version to Firefox. Whereas with the Ubuntu repos, it takes days/weeks/even months, depending.
The version in the Ubuntu repositories will only receive bug fixes during a release cycle, not new features. This version has been tested with your version of Firefox, and is fairly stable.
If you use the unpackaged version via Mozilla Addons or elsewhere, it'll receive all new updates by the maintainer of the addon. These may cause breakage, depending on the level of testing upstream puts their code through. In Adblock's case, I suspect the level of QA is high, so this is not a very pressing concern, but one to take into account nevertheless.
Firefox will refuse to install a newer version of the addon if said version no longer supports your browser version, so you don't have to worry about that.
The main difference is that the Ubuntu-packaged version is feature-stable (its behavior does not change) as well as reliability-stable (it will work consistently) throughout the release, whereas you don't get those guarantees from using AdBlock's extention installed externally.
If you're installing it for more than one user, by all means, use the packaged version. But if it's just for you, I think the locally installed version is fine.
No, the Ubuntu Firefox Modifications Extension allows this to easily be done without any problems.
To answer your question: no, it doesn't matter.
The only difference is that the version in the Ubuntu repositories will usually take a day or two longer to be updated.
If you install using the Add-On manager (as opposed to going to the website) it's my understanding that it installs from the Ubuntu repositories anyways due to the ubufox plugin.
I have more 60 extensions installed and I always get them From Mozilla. Some updates might cause problems but they are usually fixed right away, specially AdBlock and NoScript.
I would recommend using firefox's addons menu, as it is updated IMMEDIATELY when the developer of the addon pushes out a new version to Firefox. Whereas with the Ubuntu repos, it takes days/weeks/even months, depending.