There's going to be a bit of meandering before I eventually get to the point here, so bear with me, or skip the next few paragraphs to go directly to the "meat" of this post...
Six months ago, when Linux Mint Debian was released, I was really excited about it - finally a Debian-based distribution with the quality of Mint and without the baggage of Ubuntu! As I have noted in other blog posts, I installed Mint Debian right away (and its sibling Mint Xfce immediately after its release as well). A month or so ago, things really seemed to kick into high gear with Mint Debian, there was a very large batch of updates, including major changes to the Mint Update program itself, and shortly after that I realized that I had started using Mint Debian a lot more than I use Mint 11. In fact, I now use either Mint Debian or PCLinuxOS almost exclusively, I only boot Mint 11 when I have some specific reason to do so (hmmm, I didn't intend for it to sound like Windows in that description...).
Mint Debian and PCLinuxOS are both "rolling" distributions, meaning that they are continuously updated rather than being on a periodic "major release" schedule. Both have been through rough patches of one kind or another, generally related to those updates. There are two significant problems related to rolling distributions - one is managing the updates themselves, in terms of frequency, reliability and cross-update interactions, and the other is the fact that because there are so many updates it becomes tedious and time consuming to make an installation from scratch - you start to get a vague feeling of Windows when you install from the ISO and then immediately have to pick up a thousand or so updates. (It's only a very vague feeling, though - we are still talking about an hour for a scratch installation, not a couple of days.)
Both Mint Debian and PCLinuxOS have had to struggle with these problems over the past six months or so. For PCLinuxOS, after hitting their stated target of making a new base release every three months the first couple of times, there has just been a lag of six months between the 2010.12 and 2011.6 releases. That is certainly no tragedy, and I don't mean this as a criticism, I am only saying that it is a good example of how difficult it can be to stick to a schedule like that. Outside events, such as problems with hosts and repositories, can throw things way off very quickly. For Mint Debian, there have been some problems with reliability or surprising side effects of updates, or even of the update process itself. I have seen a couple of times when updates have failed (who here likes F-Spot even less now?), or the update process has hung, or during updating it asked me questions which even I have a tough time understanding and figuring out what the "proper" answer should be. In every case Mint Debian came out intact, at most after having to reboot and run update again to properly finish the updates.
So now Mint Debian is trying to do something about this, to make the updating process both easier and more reliable. The Linux Mint Blog has a description of their new concept of Update Packs. The way I see it they are offering a "bouncing release" as an alternative to the rolling release. The idea is that they will accumulate the continuous flow of updates into periodic (monthly) Update Packs, in which the updates have been through some vetting to confirm that they install and function properly and don't have nasty side effects or interactions with each other which might go unnoticed when they are first released. Now, this might sound like they are moving back to the periodic-release cycle that many (most) other Linux distributions use, but there are important differences. The biggest difference is that the users can decide for themselves how they want to participate in this alternative update model. If you want, you can just keep "rolling" with the updates as they flow directly from Debian. If you like the idea of having someone else take a lot of the pain and uncertainty out of updates, you can switch to the Mint Debian "Update Pack" repository, and only install updates after they have been grouped, tested and used for a while by others. If you want to be in between those two extremes, or you want to contribute to the distribution itself, you can get the updates immediately after they are packaged and help with the testing of installation and operation before they are released to the general user base.
It will be interesting to see how all of this works out. As I said at the beginning, I have been using Mint Debian more and more, and the only noticeable problem I have seen is that the update process has been a bit more exciting than I would like for it to be. I thought that they had already made a lot of progress on this with the recent improvements in Mint Update, but perhaps this change in update concept will improve that a lot more. The only potential problem I can see with it is that they might find that making a schedule like this, for monthly batches of updates, can be more difficult than it first appears and could turn into quite a grind. Only time will tell if they are able to find a good balance between grouping and testing to improve the update process and holding them back so much that they lose a lot of the benefits of having a rolling (or bouncing) distribution.
Update: I corrected some major brain-flatulence above, where I referred to PCLinuxOS as a Debian-derived distribution. Apologies for that.