I tend to agree with Kumar. The authors do not demonstrate a good understanding of clustering or log shipping. If you are not familiar with the MS options, you may well think that this is an unbiased article.

e.g. in clustering, load balancing is not a feature of clustering software as implied by this article. The designer of the cluster does this by implementing appropriate hardware and configuring the nodes of the cluster so that load is shared apropriately across the cluster.

And whilst an additional NIC on each node is recommended and strictly speaking it is an extra cost, when compared to the hardware typically used in a cluster, the cost of an extra NIC really is insignificant.

The discussion on storage arrays is also a bit light. Most storage arrays worth using come with cache that makes the performance of the array pretty impressive. Many storage arrays have battery backed cache that is used to cache writes to the array further improving performance.

And, looking at the architecture of of the "Sonasoft Standby Solution", it looks a lot like SQL 2005 Database Mirroring. So if you are using or planning to use SQL2005, have a look at Database Mirroring.