SUSE doesn't seem as well-known in the U.S. as Red Hat and Ubuntu, but it has a large worldwide market and is a rock-solid, well-engineered distribution. openSUSE, the free community version, is less conservative and contains newer technologies and software versions, and it is also very reliable. With respect to Red Hat and Ubuntu, who both have wonderful enterprise offerings, SUSE outperforms both of them. (Linux users are dreadfully spoiled by our vast wealth of great distros.)
SUSE has a lot of firsts in its history: It were the first to partner with IBM (in 2000) and develop a mainframe edition for IBM's System 390. Linux was still just a baby then, being barely 9 years old. Some other SUSE firsts are first commercial Linux distribution, first 64-bit, first to support Itanium and PowerPC, first to adopt OpenStack and KVM, and first to adopt reiserFS.
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