What does everyone think about transferring from a Brigade down to a Detachment?

I can't really speak to your MOS field in particular, but long ago I was given a piece of career advice as an ROTC cadet about to enter the Army. It was "stay as low as you can as long as you can" in regards to the level of organization was concerned. It turned out to be great advice both from a career aspect and personal fulfillment aspect. IMO nothing beats being at the level where the rubber hits the road, and you are working with the soldiers who are making it happen. That doesn't mean higher level staff jobs are not also important and difficult. They are, and working with and leading those soldiers is rewarding as well. But there is something special about being in the lower level units. After all the jobs I had in my career, including two company commands, a battalion command, and working at HQUSSOCOM, the one I look back on with the fondest memories was my time as a rifle platoon leader, serving with the platoon sergeant, squad leaders and soldiers from that time.

If you are moving from a staff job to a job with increased operational responsibility and authority, then it might be a good idea. If you've been at the Det level before and maxed out on duties at that level in your grade, then it's probably not a great career move. There are lots of other considerations. If the Det is in a great location or if it's workload would allow you to complete education or training that's important to you, then it could be a good idea. Also, check on the last person to have the job you may be moving into. What happened to them next? Promoted, reassigned, retired? This doesn't always mean you'll follow the same track, but it can be an indicator.

It depends on what the units are- it is not really important as much as what size unit you were in as how important the duty position was. Unless you are talking Div to Corps, etc..