I used to burn CDs/DVDs with Brasero on my old Dell PC running various Ubuntu distros, till it started producing faulty discs. There were other problems with the old machine, so I started burning discs on my Toshiba laptop (Ubuntu 10.04) using Brasero - no problems at all.

Now I've got a new Dell (Ubuntu 11.04) and, strangely, when I tried to burn some CDs with Brasero, it took 5 attempts to get 2 good discs - not a good success rate. Tried again with Open CD/DVD Creator on the Dell - no problem. 100% success.

So is it Brasero? Is it Dell? Is it newer Ubuntus? The discs haven't changed, they're Verbatim.

Any thoughts / observations / experiences?

Never used Brasero but had similar difficulties with K3b in the past.

Since I mainly write ISOs, rather than music CDs for example, I now exclusively use cdrecord for CDs and growisofs for DVDs. When I want a music CD I either use K3b (which doesn't seem to cause problems anymore) or Nero on a Windows box.

If Brasero is causing you problems (I also had problems with Brasero in the past on Ubuntu) you could try Gnomebaker, Xfburn, of K3B. Installing K3B will add a boatload of KDE dependencies to your Ubuntu system. This is not a problem. I just wanted to make sure you were aware of it.
Whatever you use, try burning your discs at the slowest possible speed. This may improve your 2/5 success rate.

Since I mostly use Slackware, I also use cdrecord to burn isos. For data DVDs or music CDs I use Xfburn, or possibly K3B.
One factor here is that Debian based distros, including Ubuntu, have replaced cdrecord with wodim since it is supposedly more free (as in freedom) than cdrecord. Wodim is supposed to work just as well as cdrecord, except that in my experience it did not. I have not tried wodim lately though since I most use Slackware which still uses cdrecord.

Brasero burns my discs just fine although the checksum ALWAYS reports failure. So it may look like a bad disc but it really isn't; there is simply some issue with certain types of burners and discs which prevents brasero from performing a proper checksum...