I use the same monitor and use it for the same purpose, but haven't experienced those issues.  How long have you had the monitor?

However, I might be able to help with your brightness issue, if it's the same issue I had.  Is your picture too white, or too bright?  Mine was too bright, but I noticed when I changed my display reference level to "Expanded" on my 360, it brought the brightness down to a nice level. 

JB