The advantages of an LTS is that it is rock solid stable and time efficient. Application crashes and OS internal errors are at an absolute minimum. Also, there is plenty of time between releases and the support window is five years, so little time is spent reinstalling and reconfiguring a system. But with new LTS releases only two years apart, you can take advantage of reasonably timely upgrades to the feature set of the OS while keeping wasted time to a minimal level (all the way down to once every five years if so desired).
The advantages of a BU lie mostly in getting more features sooner. With only six months between upgrades, performance improvements and additional features are always only a short wait away. But this comes at the cost of additional downtime in the form of reinstallations/reconfigurations (at least four of them compared to what the LTS user will have to do and as many as 10!), and additional application crashes and OS internal errors (that the LTS user will neatly avoid). Also, one of Linux's primary advantages is lost with such frequent reinstallations: a Linux install never breaks like a Windows installation always will (due to the time bomb that is the registry) so annual or biannual reinstallations are simply not necessary from a technical standpoint.
The standard advice to desktop users wondering which to use is usually to go with the BU. However, as shown above there are considerable advantages to going with LTS instead: the BU user will be dealing with downtime and headaches in exchange for very little in the way of real advantages over the LTS user who upgrades every two years. The BU user has no feature that the LTS user won't eventually get, and many problems the LTS user doesn't have to deal with. I'd go so far as to call the BU versions of the OS "open betas". Well, maybe that's a bit harsh. The BUs are every bit as stable as and install in a fraction of the time of Windows, but LTSes even more so.
Should there be a piece of hardware you'd like to use that the LTS doesn't yet support but the BU does, it makes sense to go with the BU. It also makes sense to go with the BU (indeed the alpha and beta builds as well) if you like to actively participate in the development of Ubuntu (one of the great things about Open Source!) But if your hardware is well supported, and you'd rather use the OS than develop it, going with an LTS, even on a desktop, makes a lot of sense and brings advantages for effectively no disadvantage (you will eventually get all the improvements of the BUs and avoid most of their problems).
So for my own situation my OS upgrade policy is:
- Use only LTS releases.
- Update installation media (but don't bother reinstalling) for every point release (e.g. 12.04.1; 12.04.2; etc.)
- Retain most recent previous version in addition to current version "just in case" and discard others.
- When new LTS releases, if "smooth system requirements" are met, reinstall to the new version. If not met, stay with current LTS for full support life, then upgrade to most recent Lubuntu.
If you are wondering whether to use an LTS or BU on your desktop, don't just take the standard advice and go with the BU. Consider using an LTS. As outlined above, there are real advantages and ultimately no real disadvantages, except in very specific circumstances (hardware problems, desire to help develop).
