I updated my kid's machine last week to Etch. Their machine was fine under Sarge -- this is Debian we're talking about - but I wanted to use their box as a test box for the basis of writing a new tutorial for my site. See: http://www.debiantutorials.org/content/view/103/133/
abit nf7-s, AMD athlon 2700+, gig of corsair value select, Geforce FX5500 (256MB), PATA drives...nothing fancy, obsolete or cutting edge, but custom nonetheless. Sound on the board, LAN as well.
Their desktop was installed from "base-config" so that gave them KDE and Gnome. I also installed a full complement of desktop apps for them including many games and other "edutainment" apps. THey also run the nvidia binary driver.
The upgrade took an hour because there was so much to download and install, and of course I did it the hard way -- by NOT upgrading their kernel first. When you upgrade, and there is no reason why you should not, I suggest that you do upgrade the kernel first - reboot, then remove the nvidia driver and any other kernel module drivers that you have installed...
Then change your sources.list file to use testing (etch) repos.
# apt-get update
# apt-get dist-upgrade
I noticed no issues with Xorg, all hardware was fine, all apps were fine, the system runs just as well as it did with Sarge...it boots much faster.
There are many reasons why someone running Sarge might upgrade to Etch - but there are also many reasons to stay with Sarge. It's a fine distro -- no matter the dissenters and those that pronounce the archaic nature of Sarge...look at it this way -- XP came out in '01 - sarge came out June '05. The apps are a little old when stacked up against the nature of Linux app evolution - they may be a version or a couple point versions out of current, but taken in the XP context of the current state of THAT OS - duct-tape and paper clips - if you like SArge then stay with Sarge.
Unless, of course, you are bored with its outstanding stability. But, you'll get that with Etch as well.
If you're worried about upgrading to Etch at this point -- DON"T DO IT. Why do you run Linux anyway -- to be a slave to your machine like you were with Windows? In the case of Linux, you may just want to keep current - in the case of Windows you had no choice.
I've been running Etch on my box for about 7 months. Sure, as it is an evolving distro -- call it an OS - there have been times during those months that I had to either wait for updates, do without a program temporarily, or sit in my config seat. But if you ask my kids, who are quite savy, they will tell you that Etch rules and they never have to call me to bail or otherwise help them out. If you ask me I'll say the same.
Gnome 2.14 smokes and there are some advantages to the newer kernels -- but you can have this with Sarge as well. Etch has Beagle -- but other distros do as well, even though I would not recomend running them - Ubuntu included -- still feels like it doesn't exactly know what it's doing. BUt Beagle is not fully implemented yet and after running with it for some weeks, I'm here to tell you that it's not all it's cracked up to be. Locate, find, and grep still rule.
I could sit here and write for hours about the subtle and not so subtle changes from Sarge to Etch -- but you will see that for yourself.
But I know why you asked the question -- you need someone to tell you what to do -- right -- to reinforce what you want anyway --
Upgrade. Do it. Unless you don't even run a GUI -- then screw it -- not worth your time.