maybe you already know all about this, but just to be sure we don't mix up things:
being able to Depower or not, depends on the Kite AND on the control device (Bar/Handles).
We are talking here about Ram Airs (or Softkites, or auf Deutsch: Matten). Open Cell are just plain ram air kites, with open air intakes, which makes them unsuitable for water use (they would fill with water very fast). Ram airs for Kitesurfing have "one way" air intakes, so that they can still be filled with air, but do not let it out so quickly, which means they can be landed in water and are still relaunchable.
Depower ability, on the other side, depends only on the construction of the kite.
Ram airs without depower: up to now, most of the open cells (Libre, Flexifoil etc.). With the brake lines you can take out some power from the kite, but it's no real depower. These can be flown with handles as well as bars. I find handles give you a better control, and in dangerous situations you simply let go one. Bar has other advantages (e.g. to spring), and some people prefer it.
Ram airs with depower: most modern Surfkites (Flysurfer, Advance etc.). These kites can reduce their power with a factor of 2:1, or even more. This means that through the depower, you can halve the power of the kite !
In order to work, they have to be flown with a Bar + Harness. Handles could be possible, in some cases, but are not the first option.
This also means that you have to hook in, which can be dangerous on land in gusty areas. In this case, please use a quick release system !
One more point: kites without depower usually (stress on usually!) have more power/sqm. This means you need less surface = less danger.
On the other side, kites with depower have a wider wind range and compensate gusts much better.
So what, you may ask ! If I were you I would consider following points:
- am I planning to start Kitesurfing as well ?
If yes, consider investing some more money, and buy a Kite with depower that's also suitable for water.
- Can I imagine buying more than one kite ?
If yes, considering where you live, a small/medium open cell w/out depower (3 to 4 sqm)would be a good and cheaper start. Later you might want something bigger, e.g. for snowkiting.
Last advice: just in case you don't already know it, this is a good forum in German language: http://www.kitesurfen.de/forum/index.html