Not to play devils advocate, but I do see a value in editing your own work. As a director who pays the bills by editing I call it the 1st cut approach.
I have two different recommendations for Director/Editors and it really depends on what situation you are in.
Scenario 1)
If you are directing your own movie and want to edit it, I would say that you should find someone who can do the first edit for you, that way you get another artistic vision applied to your film before you do the fine tune editing.
Scenario 2)
If you are hired on as a director or have an editor to edit your film and you still want a strong editorial voice (especially if you are hired on), then I would argue that you should do the first edit. That way, you can apply your directorial intentions into the edit so that your voice can be heard and then let the editor do their work. This has happened to me where I didn't get to do the first edit on a film and there were, in my opinion, a lot of bad editorial decisions made that I tried fighting for but was turned down by the producers...so if you can get a first cut then take it.
All in all, I think the main thing is to allow outside voice to be heard because they might have a better way of approaching something than you have.
Also, if you want editing experience, cutting your own stuff will be the easiest way, but if you are starting out, see if you can get some assistant editing jobs, then offer to cut some scenes or in your spare time do a few edits and show it to the producers...or ask if you can use it for your reel.