I both use OpenSUSE and Ubuntu servers, and, for a newbie, i do think that, while installing a LAMP server for the first time Ubuntu is far more easyer.
The setup of Ubuntu server provide "one click" configuration to get started with LAMP server, at the end of the preflight check, the installer ask wether you want to install a LAMP server ou another.
It may be controversial but Yast2 is less intutive and sometime rather boring than a synaptic packet manager or aptitude and apt-get, and, for a new user, Internet installation of opensuse may be more difficult than installing an ubuntu server version.
But, that's only my point of view
And there's some great tutorials her to get started (for both servers)
Concerning the stability issues, we do run more than one hundred websites on ubuntu 6.06 servers, and Suse Servers are not opensuse ones bit Enterprise servers.
Both keeps running well, but we do prefer Ubuntu ones for maintenance reasons.
May it help you .