I have a self freezing Cuisinart unit and have owned the type where you need to pre-freeze the container (as well as a traditional ice and salt model). If you are organized enough (and have the extra empty freezer space), the pre-freeze model works well, and is certainly less expensive than the self-freezing unit. If you want to make multiple batches in a short time period, you will need to purchase and freeze additional freezing containers, however.
The self-freezing Cuisinart unit has worked quite well for the past 9 months. I use it about once a week. It is convenient for me to be able to make ice cream without having to first remember to freeze the container (usually at least an overnight process). That said, it does work best if your mix is already fully chilled, which means that you will still need to prepare your mix in advance so it can adequately chill. Having an extra pail and dasher are handy if you plan to make multiple batches, but not necessary (unlike the pre-freezing model) as you can easily just wash in between.
Both machines are somewhat noisy - I have always run them in the basement utility room. In looking at the various models of self-freezing machines, I did not find any unit that was universally praised by reviewers. Each model seemed to have some issues or complaints. I bought the Cuisinart primarily because I got a very good deal (it was a refurb for @$150) and it had its share of both good and bad reviews. So far so good.
The traditional ice and salt model also works very well, but is messy and has a small learning curve (salt to ice ratio). The upside is that they usually have much greater capacity than the other models - 4 qt compared to 1.5 or 2 qt.
Hope that helps.