Probably not exactly the same software, there could be lots of little things that are different. But the ability to pay them for extra support is the major difference. You can generally also be certified in Enterprise versions.
If you’re interested in the differences, most of the time you can probably find those fairly easily. It helps with their marketting.
The wiki for SUSE explains it pretty well:
####OpenSUSE vs SUSE Linux Enterprise
OpenSUSE is a freely available, community project that releases versions comparatively, on a frequent basis and generally, uses the latest versions of the various open source projects that it includes.
SUSE Linux Enterprise is SUSE’s commercial edition, which SUSE releases much less frequently, enabling it to offer support more effectively for enterprise and production deployments. It is certified for a wide variety of enterprise applications and offers a number of special enterprise features including, High Availability and Point of Sale extensions. SUSE historically uses a heavily-tested subset of packages from OpenSUSE Linux as the basis for SUSE Linux Enterprise.