To clarify, I use MS clustering for local failover high-availability in an active-passive configuration and no way implied clustering as site failover alternative. For failover to our remote site which is more than 1,000 miles away we use SAN based EMC SRDF/A to identical H/W at our dark site. We too manually swing the DNS entry upon failover to the remote server and both the DNS swing and EMC commands are scripted. Our failover time even with mounting the R2s is is pretty close to the time it takes to swing the DNS entry.

Based on my experience, yours may vary, I can state the following generalizations:

Hardware solutions such SRDF/A are generally better than S/W solutions such as Data Mirroring.

Our spend on a hardware i.e. SAN solution is much more than the spend on S/W solution using DM.

Data Mirroring I would characterize as similar to log shipping i.e. phyiscal operation of replaying log restores to a remote host. Having used log shipping both the MS delivered and customized for several years and given the choice over DM/Log Shipping and H/W based disk replication I would choose disk based replication. And finally having run disk based replication over SRDF/A for over two years, I can attest that it works and requires 0 DBA hours. I can not say the same for log shipping. I would also state that SRDF/A is generally better than MirrorView/A (You get what you pay for).

My two biggest complaints with DM is that it requires rewriting your applicaitons to be DM aware if you want automatic failover and it is a physical operation instead of a logical operation.