There are many things that can be said about subtitles or dubbing. Some anime fans will tell you dubbed is the way to go, while others will pull for the authantic feel of subs. In the end all it really is is personal preferance.

With dubbing you don't have to constantly read words on the bottom of your screen. This can be a big thing if you have difficulty watching the show while reading the dialogue. The whole show will be in your language. Also, dubbing makes certain things in anime easier to understand. In subtitling some companies or fansubs are really exact, which makes the translated sentences seem choppy. Dubbing is more consise, it's clear, with no extra words added. Voice actors is also another big deal. Many people protest dubbs because of 'bad voice acting'--in reality, voice acting has much improved in English released animes, though you'll still get some bad ones that make you want to cringe. Most of the time the words even come out in sinc with the lips moving. The downsides are you may miss important plot points when they cut certain dialogue to make the show easier to understand, or to make the lip movement in sinc. You still will get some really horrible dubbing, it's out there. Also, many shows that are dubbed are also edited, so it really messes with them. This may not be as true as it once was, but it still is at least in part. (especialy for those shown on tv). In Naruto they have done a much better job then some, It's not prefect but very good in light of some of the ones I've seen. Another important thing that some people miss is that some things don't really translate These things don't exist in english and it works the other way too. This does make those that watched the sub either confused or mis-understand.

Dubbing is more difficult because good dubbing not only gives the viewer an accurate translation of the original, but also matches up the performed translation with the lip movements of the onscreen characters. To further complicate matters, the character's gender, ethnicity, social status and age needs to be matched in their voice portrayal. Some things like gender and age are easily matched. However, social status and ethnicity are completely different animals altogether. In some cases, the culture that the show is translated into just doesn't have the kind of social class that is portrayed, for instance, nobles versus warriors versus commoners in Crouching Tiger, Hidden Dragon (I'll use a non-anime, but it still proves this point as who hasn't seen this movie). The biggest constraint that dubbing runs up against is lip synchronization between the translation and the on-screen characters.

It's up to you